Foreign fighters in Syria and Iraq: The day after
In this Lowy Institute Analysis, Research Fellow Dr Rodger Shanahan and Nonresident Fellow Lydia Khalil argue that an increasing number of foreign fighters are likely to leave Syria and Iraq in the coming months and years, especially after the collapse of Islamic State’s caliphate, exacerbating the terrorist threat faced by the international community. Shanahan and Khalil highlight both the scale and nature of the long-term security threat that the foreign fighter cohort will pose, and ways in which the international community can ameliorate the threat.
Photo: Getty Images/John Moore
- The length and intensity of the Syrian and Iraqi conflicts will mean that those foreign fighters who survive will likely be the most operationally experienced, lethally skilled and highly networked group of jihadis to date.
- It will be impossible to contain the outflow of foreign fighters given the multiplicity of options available to them, and they will not all follow the same pattern of activity post-conflict. Security agencies will face difficulties in determining the threat each fighter is likely to pose and in allocating resources to deal with these individuals.
- Given the nature of a globalised society, national approaches to this foreign fighter problem will be insufficient to address the issue. A coordinated global approach, with all the difficulties this entails, is the only effective way in which to contain the threat.
In the last five years, Western counterterrorism agencies have focused largely on radicalised individuals going to Syria and Iraq. Now and in the immediate future they will need to focus more on those coming out. The prospective collapse of Islamic State’s ‘caliphate’ is likely to increase the number of foreign fighters leaving its territory. More generally, the foreign fighter fallout from the years of conflict in Syria and Iraq will echo that of previous conflicts such as Afghanistan and Bosnia. The fighters who survive and escape will be just as ideologically motivated as those that emerged from Afghanistan and Bosnia, but will be more operationally experienced, have more lethal skills and be better networked than their predecessors.
It is critically important that international security agencies understand the networks that these individuals have formed, the routes they intend to use to leave Syria and Iraq, and their intentions once they have left the battlefield. This will require a more coordinated international response rather than just multiple national approaches. This should include common legislative action regarding the treatment of foreign fighters, greater intelligence and border control coordination and cooperation and a greater focus on the foreign fighter issue within existing multilateral counterterrorist groupings.
The Syrian conflict is now in its fifth year. Its scope has expanded beyond a civil war, or a regional power struggle; today it is a multilayered conflict with global implications. Of particular concern to the international community is the tens of thousands of foreign fighters from over 100 countries who have been drawn to the conflict. While not all these foreign fighters have ended up serving with jihadist groups, a significant proportion have. The war in Syria has given new life to established groups such as al-Qaeda, and has raised to prominence newer groups, most notably Islamic State. From its self-declared ‘caliphate’ in Iraq and Syria, Islamic State has used a sophisticated propaganda campaign to recruit foreigners to its ranks. Increasingly, the group is using foreign fighters to carry out terrorist attacks outside of the Middle East, such as those in Paris in November 2015 and in Brussels in March 2016.
In the last five years, Western counterterrorism agencies have focused largely on radicalised individuals going to Iraq and Syria. In the next few years, the focus will be on those coming out. Indeed, this shift is already occurring. While there has been a steady stream of foreign fighters leaving Iraq and Syria for some time now, these departures are likely to increase as a result of developments on the ground. The US-led military campaign against Islamic State has, in recent months, made major inroads into the territory controlled by the group. Islamic State has suffered significant battlefield losses and is preparing its followers for the fall of its remaining strongholds. These setbacks will increase the pressure on some foreign fighters to leave Iraq and Syria. The group is already encouraging potential recruits to go directly to other Islamic State outposts, most notably in Libya, or to stay in Europe to launch attacks as part of its global campaign.
Unfortunately, the end of Islamic State’s caliphate will not mean an end to the threat posed by the group or by the foreign fighters who have flocked to it and other jihadist movements. The jihadist threat will not diminish — in fact, it is likely to become more diffuse and complex. The fall of Islamic State’s caliphate will simply represent the end of one phase of a much longer campaign against violent jihadist groups. The fighting in Syria and Iraq has helped to create the basis for an extensive global network of foreign fighters in much the same way that the war against the Soviet Union in Afghanistan in the 1980s and 1990s created the basis for al-Qaeda’s global networks. The difference this time is that the jihadist networks will be larger and more lethal than those that emerged from Afghanistan.
The aim of this Analysis is to understand the future of the foreign fighter problem in coming months and years. It takes as its starting point the prospective demise of Islamic State’s territorial stronghold in Iraq and Syria in the short term, but also growing military pressure on other jihadist groups such as Jabhat Fatah al-Sham (formerly Jabhat al-Nusra). Against that background it examines the options open to those foreign fighters who have joined jihadist groups. For those seeking to leave, this Analysis assesses their potential exit routes, as well as their possible destinations. It concludes with a number of recommendations for policymakers and security agencies to help address the challenges that this new phase of the foreign fighter problem will pose.
Islamic State’s demise
In December 2014 the United States formed the Global Coalition to Counter the Islamic State of Iraq and the Levant (ISIL), an international coalition that included Australia. The goal was to destroy Islamic State and to win back the territory in Syria and Iraq that the group had captured. Since then the coalition’s military campaign against Islamic State, while cautious and often criticised by outside observers, has had a significant impact. Brett McGurk, US Special Presidential Envoy to the Global Coalition to Counter ISIL, stated that the strategic intent of the campaign was to “degrade and suffocate” Islamic State over time. Working with indigenous forces on the ground, and using coalition air assets, the Global Coalition has targeted the group’s leadership, and its command and control and logistic capabilities. Most recently a coalition airstrike killed Abu Mohammad al-Adnani, a senior leader of Islamic State and the group’s official spokesperson.
The coalition’s intervention, along with the manoeuvrings of Russia, Turkey, and Iran in Syria, has seen Islamic State lose substantial territory. In 2016 it has lost Manbij and Palmyra in Syria, and Ramadi and Fallujah in Iraq. Preliminary operations for the retaking of Mosul by coalition and Iraqi forces have commenced. US officials estimate that Islamic State has lost almost half the territory it once held in Syria and a fifth of its territory in Iraq.
Islamic State still controls Mosul and Raqqa as well as some income-producing assets such as oil infrastructure. It also holds important territory on both sides of the Euphrates, giving the group access to roads and infrastructure and allowing it to connect territory between Iraq and Syria. Islamic State’s loss of its last stretch of border territory between Syria and Turkey, which had served as its principal supply route, will place further pressure on the organisation. With this territory now lost, Islamic State will find it increasingly difficult to maintain combat effectiveness and administrative control over what remaining territory it holds.
But alongside these territorial setbacks, the group has also suffered significant financial losses. The coalition’s air campaign has targeted Islamic State’s cash storage points and oil installations. The gradual loss of crossing points along the Turkish border reduced the flow of goods and money into the caliphate. These financial losses have, in turn, exacerbated the group’s governance shortcomings. It is estimated that two-thirds of its budget is directed towards military spending. Islamic State has imposed new onerous forms of taxation and increased fees for services, and is reported to have cut fighters’ salaries by 50 per cent.
Islamic State is struggling to retain and recruit fighters, and not only because it is having difficulty paying them or supporting them logistically. There has been a significant drop in the number of new foreign fighters entering Syria and Iraq due to tighter border controls in Turkey and more effective screening of potential foreign fighters in source countries. Higher casualty rates among foreign fighters in Syria and Iraq have also discouraged new recruits. The Pentagon estimates that the number of foreign fighters seeking to enter Syria and Iraq to join Islamic State has dropped by 90 per cent.
Although such data is difficult to gather and even more difficult to verify, there are also reports of Syrian and Iraqi fighters leaving the group. This is an important indicator of the group’s decline given that Islamic State relies heavily on its indigenous members for a range of key functions including intelligence gathering, logistical support, and brokering alliances with local tribes. Any increase in such defections would represent a major threat to the group’s ability to operate effectively in the areas it still controls. There have also been media reports of conflict between local and foreign fighters within Islamic State. According to one account, foreign fighters have caused tensions because of their poor regard for local customs and tribal ways. Battlefield and financial losses have exacerbated these tensions.
As its hold on territory and its governance capacity diminishes, Islamic State will seek other ways to preserve itself. Islamic State’s model of a quasi-state with broad governance and administrative ambitions will give way to an organisation with a more atomised structure and a limited hold on territory. However, it will seek to remain relevant by targeting its enemies in the region and abroad through a global campaign of terrorism. Recent statements by Islamic State suggest that the group is preparing for this transformation from a semi-conventional military to a diffuse international terrorist group that seeks to survive, regroup, and later expand. A statement released in May by the late Abu Mohammad al-Adnani once again called for Islamic State followers to attack enemies wherever they are and confirmed that Islamic State will fight on in Syria and Iraq despite its losses. But he also included a new component to this familiar message, stating that Islamic State “does not fight for territory” and that its mission will carry on even if its cities fall back into “crusader” armies’ hands.
The foreign fighter problem
Regardless of what happens to Islamic State, the tens of thousands of foreign fighters who have participated in the Syrian and Iraqi conflicts, and who have fought for a variety of jihadist groups, will pose a major security threat to the international community for decades to come. Estimates of foreign fighter numbers vary. In his February 2016 testimony to the US Senate Armed Services Committee, the Director of National Intelligence, James Clapper, estimated that 36 500 fighters from more than 100 countries (including at least 6600 from Western countries) had travelled to Syria since 2012. In July 2016 the head of the United Nations Counter-Terrorism Committee claimed that there were almost 30 000 foreign fighters operating in Syria and Iraq.
In June 2016 the Director of the Central Intelligence Agency (CIA), John Brennan, claimed that total Islamic State fighter numbers had dropped to between 18 000 and 22 000 from nearly 33 000 the year before. There are no exact figures, however, as to what proportion of that overall number are foreign fighters. The leader of Jabhat Fatah al-Sham, Muhammad al-Jawlani, has claimed that around 30 per cent of his fighters are foreigners. Estimates of the strength of this group vary from around 5000 to 10 000. Even if the group’s numbers were at the lower end of these estimates, it would mean that there are at least 1500 foreign fighters affiliated with Jabhat Fatah al-Sham. The numbers reflect both the group’s reduced geographic footprint and stricter vetting procedures. Much smaller cohorts of foreign fighters also operate with a range of other jihadist groups. Moroccans and Tunisians have been reported fighting for Ahrar al-Sham, for example. Very small numbers of foreign fighters, including Australians, have also fought with Kurdish opposition forces, such as the Syrian Kurdish People’s Protection Units (YPG).
While foreign fighters do come from a range of countries, the overwhelming majority come from the Middle East and North Africa (Table 1). Significantly, however, compared with the war in Afghanistan in the 1980s and 1990s, there are more foreign fighters from Western countries.
Table 1: Foreign fighters in Syria and Iraq by region of origin
Source: The Soufan Group, Foreign Fighters: An Updated Assessment of the Flow of Foreign Fighters into Syria and Iraq (New York: The Soufan Group, December 2015), 5.
According to open source analyses of available foreign fighter statistics, 12 countries make up at least 75 per cent of the foreign fighter contingent in Syria. Tunisia (with 6000–7000 fighters), Saudi Arabia, Jordan, Turkey, and Russia (around 2500 each), and France and Morocco (1500–1700 each) account for the bulk of the source countries. Indonesia, Egypt, the United Kingdom, Germany, and Lebanon are estimated to have provided between 500 and 1000 fighters each.
The scale and speed with which foreign fighters have travelled to the current conflict zone also outstrips other conflicts in Muslim countries that have attracted foreign fighters. Between 1992 and 1993 up to 5000 foreign fighters moved to Bosnia to undertake jihad; several hundred Arab fighters went to Chechnya in the late 1990s; and during more than a decade of fighting in Afghanistan (1978–1992), between 5000 and 20 000 foreign fighters participated in that conflict, with only a few thousand foreign fighters present at any given time. Indeed, the number of foreign fighters from Western Europe participating in the conflicts in Syria and Iraq has already exceeded those mobilised from the same region for the wars in Bosnia, Chechnya, and Afghanistan combined. There are many reasons for this. They include the relative ease of travel to Syria and Iraq; rapid advances in communications technology that have facilitated recruitment worldwide; and the strong facilitation networks in neighbouring countries seeking to overthrow the Assad regime in Syria.
However, it is not just the number of foreign fighters that is higher; the current cohort is also emerging from Syria and Iraq with more lethal skills. Many of the foreign fighters who went to Afghanistan in the 1980s had limited exposure to combat or even training; for some it was more akin to adventure tourism. The result of the intensity and duration of combat in Syria and Iraq will be a cohort of foreign fighters more experienced and battle-hardened than those from previous jihads. Those foreign fighters who survive will be more skilled in a range of activities: weapons handling; constructing and employing sophisticated improvised explosive devices; information operations; covert communications; and operational planning. Their ability to mentor and train recruits will also be greater than previous generations of foreign fighters. Some will have command experience. Others will have contributed to and learned from the group’s cutting-edge propaganda machine and media capabilities.
Foreign fighters have also participated disproportionally in Islamic State’s acts of extreme violence and savagery. More unfettered than local recruits unwilling to brutalise relatives or neighbours, foreign fighters have often been used to control local populations and apply extreme violence. Chechen foreign fighters committed one of the more gruesome acts of killing by Islamic State when they burned alive captured Jordanian pilot Muath al-Kasasbeh.
Many of these foreign fighters will emerge with deep ideological beliefs given the years of indoctrination they have experienced. Some will nurse strong resentments against their own governments and the West, blaming their defeat on the West’s military campaign and their governments’ complicity in it. These individuals will represent a long-term security threat and could act as passive or active recruiters, operational planners, trainers, and jihadi proselytisers for another generation of fighters and domestic terrorists. Even those foreign fighters returning from the war in Syria and Iraq more disillusioned than some of their counterparts will have difficulty reintegrating into mainstream society. They will also still carry with them the lethal skills and knowledge of networks that might be put to nefarious purposes, from terrorism to violent criminal activities.
In previous conflicts, such as those in Afghanistan and Bosnia, some foreign fighters have gone on to become the next generation of global jihadists. Osama bin Laden, Ayman al-Zawahiri, and other ‘Afghan Arabs’ coalesced into what would become al-Qaeda after the Soviet–Afghan war. Foreign fighters of Algerian origin, such as jihadi leader Fateh Kamel who fought with the al-Mujahid Brigade in Zenica, went on to plot attacks and recruit in the West after their stints in Bosnia.
Of course, not all foreign fighters in Syria and Iraq will want to continue fighting. There are likely to be a variety of outcomes. Many foreign fighters will be killed, including those prepared to die making a last stand. Some will become disillusioned and retire to neighbouring countries or try to return to their country of origin, particularly as the military pressure and casualties build and their group’s hold on territory becomes more tenuous. However, for many of the fighters, both foreign and local, the desire to continue fighting a violent jihad will remain. Some will stay in Syria and Iraq; some will relocate to other countries or conflicts with a strong jihadist presence such as Libya or Yemen; and some will seek to promote and recruit for jihad in Western countries, directing, inspiring or supporting terrorist attacks, or even carrying them out themselves.
For the purpose of this Analysis we have divided the future foreign fighter cohort in Syria and Iraq into four categories: those who chose to remain in Syria and Iraq; those who leave in order to continue violent jihad in another theatre, either at home or elsewhere; those who seek to return to their country of origin; and those who go to a third country of refuge. Each of these groups will present unique challenges and require separate responses to the threats that they will pose.
If the military campaign against Islamic State continues to win back territory in the next 6 to 12 months, it is still highly likely that significant parts of Syria and Iraq will remain ungoverned or semi-governed for the foreseeable future. Competing interests among various domestic and international stakeholders in Syria will make a decisive settlement to the Syrian conflict difficult to achieve. In Iraq, continued worries about the Shia-dominated government and Kurdish forces controlling Sunni majority areas without proper power sharing will mean Sunni tribes remain wary of any national government manoeuvrings.
This means there will continue to be a hospitable environment for jihadist groups and foreign fighters to operate in, even after Islamic State’s caliphate is gone. However, much will depend on what local connections foreign fighters have formed, how they are viewed by local communities, and what support they receive from local comrades in arms. There are precedents for foreign fighters remaining in conflict zones after a campaign has ended. In the case of Bosnia, for example, despite the fact that the Dayton Accords called for all foreign fighters to leave, many were given Bosnian citizenship if they had married local women, or if they were unable to return to a safe country. The circumstances in Syria and Iraq, however, are quite different. In Bosnia foreign fighters typically fought under the banner of the Bosnian army and were rewarded as a result. It is likely that foreign fighters will be entirely less welcome in post-conflict Iraq and Syria. Those associated with Islamic State will be at a particular disadvantage. The group’s often extreme violence and efforts to dominate the jihadist milieu means it is intensely disliked at almost every level. Islamic State did not seek to build alliances with other groups so once it has lost its territorial base and momentum it is unlikely to retain a support base, especially in Syria. Should foreign fighters seek to establish a new life within Syria but outside of a fighting group, they will find an inhospitable environment given the lack of community support.
Much of the senior leadership of Islamic State is, however, Iraqi. Given the continued inability of the Iraqi Government to control the country, it is possible that some of its senior leadership located in Syria may seek shelter within areas of Iraq where they still have support or tribal links. In their earlier incarnation as members of al-Qaeda in Iraq, many of the current leaders of Islamic State were able to recover from the impact of the successful counter-insurgency campaign fought against them in the mid-2000s by US and Sunni Arab ‘Awakening’ forces. They slowly and patiently recreated their organisation, and they may believe that they can withstand the latest setbacks and rebuild over time. This view that decline and revival are part of Islamic State’s path of history was referred to in a June edition of its weekly Arabic newsletter, al-Naba. It is possible that Iraqi members of Islamic State who are able to find refuge among supporters in Iraq will include some foreign fighters deemed integral to the group’s future survival.
One option for foreign fighters once Islamic State’s formal structures collapse will be to join other groups such as Jabhat Fatah al-Sham. The two groups have had an uneasy and at times antagonistic relationship. Jabhat Fatah al-Sham rejected Islamic State leader Abu Bakr al-Baghdadi’s claim to be the caliph, or leader, of the Muslim faithful, as well as the ultra-violent methods of the group. But many of Islamic State’s foreign fighters have served with Jabhat Fatah al-Sham in the past (under its former name Jabhat al-Nusra). It is possible, therefore, that a number of them will also migrate back to Jabhat Fatah al-Sham.
Jabhat Fatah al-Sham, which operates in Syria, has been more assiduous in its cultivation of other armed Syrian groups as allies. As a result, it is generally much better regarded than Islamic State in its respective areas of operation. It is also considered to be more efficient with well-resourced fighters and a greater proportion of Syrians among its ranks than Islamic State. This means that foreign fighters serving with Jabhat Fatah al-Sham are more likely to remain behind. The group’s stronger local links and less violent behaviour towards non-combatants also means it is more likely that local populations will provide support to the group, even after the conflict is over, as a form of insurance against excesses that the central government’s forces (whatever they look like) may try to perpetrate in the future.
A second category of future foreign fighters will be those seeking opportunities to continue fighting violent jihad elsewhere, either as members of Islamic State or other jihadist groups, or as freelancers.
Islamic State’s willingness to use foreign fighters to launch terrorist attacks in Western countries is already evident, as is its use of disaffected Muslims, inspired by online campaigns and in some cases by active handlers, to direct attacks in the West. Several of the 11 terrorists involved in the November 2015 attacks in Paris had returned from Syria. Returnees also featured in the Charlie Hebdo attack in Paris in January 2015 (in this case brothers who had trained with al-Qaeda in the Arabian Peninsula in Yemen), the Brussels attack in March 2016, and a number of other smaller attacks and foiled plots.
There has been a strong correlation between Islamic State’s territorial losses and military defeats with its international attacks. While the group was able to expand and gain territory in Iraq and Syria, its focus was on state building and governance. Once it started to experience territorial losses, the group’s spokesman, the late Abu Mohammad al-Adnani, shifted tone, calling on Islamic State supporters not to come to the caliphate, but to attack Western forces wherever they could, especially the “spiteful and filthy French”. To back up his calls, al-Adnani set up an international operations unit under his supervision. Abdelhamid Abaaoud, coordinator of the Paris attacks, appears to have been a member of this unit. Australian Mohammad Ali Baryalei, killed in an air strike in late 2015, was also purported to be part of the effort to encourage attacks abroad.
Indeed, a spate of small-scale attacks in the West previously thought to be inspired, but not directed, by Islamic State were later found to be part of a wider strategy. Defectors from Islamic State have claimed that recent losses and the decline in foreign recruits has led to the group’s high command rethinking how foreign fighters and potential foreign recruits can best serve the organisation in the future. According to one defector, “… they are trying to make sleeper cells all over the world” and some foreign fighters have already left Islamic State and returned home to carry out this strategy.
Islamic State has since elaborated in its French online magazine that they are adapting a directive control planning strategy under the command of a security intelligence unit, known as al-emni, which calls for commanders to provide a goal and time frame but giving no operational direction and leaving no obvious traces to central command. One recent media report has claimed that Islamic State has created “a multilevel secret service” with a “tier of lieutenants empowered to plan attacks in different regions of the world”. The plan is for these operatives to link up with new converts, or ‘clean’ recruits, interested in carrying out attacks and pass along instructions or provide propaganda support. The result is likely to be different styles of attack: low-tech attacks by individuals inspired by Islamic State; and more complex attacks facilitated or carried out by Islamic State operatives or former foreign fighters in conjunction with ‘clean’ recruits.
Islamic State has also been attempting to establish outposts in a number of Muslim countries. Because most foreign fighters come from the Middle East and North Africa, these regions are the most vulnerable to the establishment of Islamic State outposts. In many cases, however, the ‘branch’ of Islamic State is simply a local jihadist group that has sworn loyalty to Islamic State, or taken its name. In other cases, Islamic State has sent core members to either establish or support a branch (see Appendix A).
Libya has been particularly fertile ground. A country in chaos with no functioning national government, and a vast array of warring militias, Islamic State’s presence there has reportedly grown to between 5000 and 8000 fighters. While Islamic State’s hold on its Libyan base may be precarious, its presence has already deepened and complicated the jihadist threat. There are reports that some Libyan Islamic State members have defected to other Islamist militias south of Sirte.
Likewise, Islamic State has established itself in Yemen, long a stronghold of the operational franchise al-Qaeda in the Arabian Peninsula (AQAP). The Director of the CIA, John Brennan, has singled out Islamic State’s Egyptian affiliate as the most active and capable terrorist group in Egypt. As foreign fighters leave Syria and Iraq, their numbers in these and other outposts are expected to swell. One interesting question that this raises is the relationship between local members of Islamic State in these countries and any foreign fighters who gravitate to these locations.
Other parts of the Muslim world are also likely to see Islamic State outposts or feel the impact of returning foreign fighters. As Table 1 indicates, a significant number of foreign fighters from Southeast Asia have made their way to Syria and Iraq. Their motivations have varied: in some cases whole families have travelled to Syria out of a religious conviction that events in the region herald ‘the end of days’; others have gone specifically to gain training and expertise to take back to their home countries. Not all serve with Islamic State; some have joined Jabhat Fatah al-Sham. Indeed, among Indonesian extremist groups there are splits and tensions depending on which group they align with in Syria.
The Indonesians and Malaysians serving with Islamic State were originally formed into a Southeast Asian brigade, the so-called Katibah Nusantara, based in Hasakah in Syria. Since then splits have reportedly occurred in the brigade, motivated largely by a struggle between rival leaders within the group. These leaders maintain contact with their supporters in Indonesia and have on occasion provided some funding to these supporters. In June 2016 Islamic State released a Bahasa language newsletter. A video was also released that urged Islamic State supporters unable to travel to Syria to go to the Philippines to conduct jihad. A Malaysian Syrian returnee, Murad Halimmuddin Hassan, and his son were tried and sentenced on terrorism charges in June 2015, with Murad having returned to Malaysia to act as a spiritual leader for those who wanted to perform jihad. Malaysian authorities have arrested more than 100 nationals because of their ties to Islamic State.
Foreign fighters may also find their own way to other conflicts in the Muslim world, even without the direction or support of Islamic State or other jihadists groups. The future sites of jihadist activity will unfold over time as the fighters regroup, re-establish networks, and seek out ungoverned or semi-governed spaces in which they can operate.
A third category of future foreign fighters will be those seeking to return to their home countries and who have no intention of continuing with violent jihad. They may have become disillusioned with the war in Syria or Iraq; or they may feel they have fulfilled their duty. Indeed, a significant number of foreign fighters from a range of terrorist groups have already left Syria and Iraq. So far, however, there have been relatively fewer foreign fighters from Islamic State because of the group’s often severe punishment of defectors and deserters. But as the caliphate collapses, the ability of the group to control departures will diminish.
The intention of these former fighters to abandon violent jihad, insofar as it can be accurately assessed, does not necessarily reduce the threat that these individuals pose. Some will be genuinely disillusioned with what they found when they decided to travel to Syria or Iraq. Some will have found the experience too physically demanding and emotionally difficult for them to endure. Others will have been disillusioned by how much time they spent fighting other opposition groups rather than the Assad regime, or by the fact that the activities they were compelled to participate in did not fit with the ‘Islamic’ path they believed they had set out upon.
Yet the lethal skills that these individuals carry will make their presence in home countries a significant security concern, even if their initial intention is to abandon violent activism.
Little research has been done on the motivations of former foreign fighters and why they disengage from or re-engage in terrorism. What research has been done simply highlights the difficulties in achieving a good understanding of returnees’ motivations. For example, the International Centre for the Study of Radicalisation and Political Violence in its study on Islamic State defectors noted that returnees had “an incentive to downplay their ideological commitment, the role they played in crimes and atrocities, and … say whatever they think will save them from prosecution or worse”.
There is no single pattern for the actions of returned foreign fighters. Much will depend on the kind of interactions they experience with family, the community, and law enforcement and counterterrorism agencies once they return home. Deradicalisation and reintegration programs offer one pathway for returnees, but they remain a work in progress and have had mixed results. The families of foreign fighters who may have joined them in Syria or Iraq or the children who may have been born while their families were there will also need to be considered within this group. Because the intentions of former foreign fighters may evolve, security agencies will be left to make difficult judgements about where to allocate finite surveillance resources among the many returnees that they will have to deal with.
The fourth category of future foreign fighters will be those leaving Iraq and Syria to go to third countries. This group straddles both the ‘global jihadis’ and ‘the veterans’ categories. In some cases these will be foreign fighters who have been sent to other countries to support the group’s activities, as discussed above. In other cases they will be jihadist fighters who cannot return to their home countries because they have had their passports cancelled or because they could face criminal charges; a small minority may have had their citizenship stripped as well.
In some cases the move by a foreign fighter to a third country may have been facilitated by connections formed in Iraq or Syria. One example is the case of four ethnic Uighurs arrested in Indonesia in September 2014 en route to a terrorist training camp in South Sulawesi. The decision to send them to Indonesia was the result of connections between Uighur and Indonesian jihadists serving in Syria and in part a function of the growing difficulty that Uighur foreign fighters were having in getting to Syria. Since then a number of Uighurs have been sighted in the ranks of the Indonesian jihadist Santoso and a small number have been killed by Indonesian security forces. Santoso himself was killed by Indonesian security forces in July 2016.
This group of foreign fighters poses particular problems for security agencies, in large part because they do not fit the usual category of foreign fighter. Westerners appearing in Southeast Asia or North Africa, for example, would be able to pass more easily through security in tourist locations than would locals, and therefore would have a comparative advantage when planning terrorist attacks. The presence of third-country nationals also raises difficult questions regarding intelligence sharing, particularly between countries with differing views on capital punishment.
The departure of foreign fighters from Syria and Iraq raises the question of likely exit routes for these individuals. Apart from those individuals that may return to Iraq from Syria, the main exit routes will be across one of Syria’s three land borders with Lebanon, Jordan, and Turkey.
At the start of the conflict only a relatively small number of foreign fighters gained access to Syria via Lebanon, and the movement of jihadists into Lebanon from Syria has continued to be limited. Lebanese authorities interviewed for this Analysis believe that only Lebanese and perhaps some Syrian fighters may seek to leave Syria through Lebanon, although others may eventually find their way there through a more circuitous route depending on their ultimate intent. Exit through Lebanon remains difficult due to the need for contacts within Lebanon to facilitate such travel and also because much of the border area is either controlled by the Syrian regime and its allies or is heavily policed by the Lebanese military. This level of risk is only likely to be accepted by those foreign fighters with significant links inside Lebanon to justify the journey. However, the failed attempt by eight suicide bombers to enter Lebanon via the Lebanese border town of Qa’a in June 2016 shows that all options for travel out of Syria should be considered.
The exit south via the Jordanian border would also be difficult for foreign fighters. At less than half the length of the Turkish–Syrian border, the Jordanian authorities have been much more successful in controlling their border with Syria. The border has also been physically secured as part of a US$100 million Pentagon-funded border security program for Jordan and Iraq. Jordan also has highly effective internal security policies and agencies.
Turkey, therefore, remains the most likely crossing point for foreign fighters seeking to exit Syria or Iraq. A sophisticated smuggling network has emerged since the Syrian conflict began. Islamic State’s border chief, Abu Muhammad al-Shimali, is a key facilitator of the movement of foreign fighters in and out of Syria and was implicated in the exfiltration of some of those involved in the 2015 Paris attacks. The current purge of members of the Turkish security forces in the aftermath of the attempted coup on 15 July could result in a loss of institutional knowledge and in general the country’s domestic political turmoil may distract Turkey from the task of tightening its borders.
Turkish authorities do, however, appear to be passing information to foreign countries on fighters transiting their country, although the lack of any form of commensurate evidentiary trail makes prosecutions difficult. There is evidence that Turkish authorities have recently been more willing to detain foreigners (in particular Westerners) entering or leaving Syria, particularly if sufficient information is provided to them by requesting countries. In the period from 2011 to March 2016 Turkish authorities claim they deported around 3250 foreign fighters and in 2016 Turkey claimed that it had detained 1654 Islamic State suspects, half of whom are foreigners. But it is unrealistic to expect Turkish authorities to be able to arrest all foreign fighters crossing into their territory, especially if the numbers increase substantially in the coming months and years.
Given that over half of the foreign fighters transiting Turkey are Arab nationals, there is also the question of what Turkey would do with those they detained. Ideally it would want to hand them to authorities from their home countries, but Turkey only has extradition treaties with some of these. Turkish authorities are conscious of the risk that Turkey could also become an even bigger target of the terrorist groups if it began to systematically detain their members. In interviews for this Analysis, some Turkish interlocutors also noted that while Western countries have long demanded that Turkey do more to tackle the foreign fighter problem, they have done little to address Turkish complaints about the lack of prosecutions against Westerners fighting for Kurdish groups in Syria and Iraq. There will also be continued friction between Washington and Ankara if the United States does not respond positively to Turkey’s demands to extradite Fethullah Gülen, whom they claim instigated the attempted coup in July 2016.
All of this suggests that Turkish authorities will prefer to see departing foreign fighters quickly transit their territory, while perhaps detaining higher-profile fighters such as those from Western countries. Indeed, once in Turkey, foreign fighters have a range of options for onward travel. The country boasts 16 international airports, and there are well-established land and sea smuggling routes to Europe or North Africa. There are also options to transit by land or air to the east into the Caucasus or Central Asia.
The impact of trained, experienced, and networked foreign fighters on both conflicts in the Muslim world and the terrorist threat faced by non-Muslim countries cannot be underestimated. The influence of the Afghan generation of foreign fighters were felt everywhere from Chechnya to Bosnia. Foreign fighters were, for example, pivotal in improving the standard of Chechen fighters in the mid-1990s. A significant number of terrorist attacks in Indonesia in the early 2000s, including the 2002 Bali bombings, were led, or carried out, by elements of the Indonesian terrorist group Jemaah Islamiyah who had received training in Afghanistan. A particular concern for counterterrorism agencies will be the ability for returning foreign fighters to ‘professionalise’ domestic terrorist groups and to act as mentors and sources of inspiration. The addition of even a small number of returnees with planning and combat experience, and with links to facilitation networks, has the potential to increase the frequency and lethality of future terrorist attacks in a wide variety of countries.
Moreover, the nature of this threat cannot be thought of in simply national terms. It is not just a matter of foreign fighters returning to their home countries. The war in Syria and Iraq has created a significant cohort of lethally trained and networked fighters who will infect the arteries of the international system. Some will participate in acts of terrorism; precedents suggest others could end up as members of international criminal syndicates. Returning foreign fighters need to be regarded as a systemic problem rather than a purely national one. These individuals pose a threat not only to the countries to which they return, but to all countries whose citizens travel and trade in the international system.
It will be almost impossible for counterterrorism agencies to completely prevent any of the scenarios outlined in this Analysis. But through effective policies and greater coordination it should be possible to minimise their longer-term impact. The current military campaign against Islamic State and groups like it is an important starting point. Reducing the foreign fighter threat at its Syrian and Iraqi sources cannot be the end of what will be a long campaign. Bringing a quick end to the conflicts in Syria and Iraq is critical to ensuring that Islamic State is not simply replaced by a new jihadist group. It will also be necessary for the post-conflict political solutions in Syria and Iraq to address deep-seated concerns regarding poor governance, sectarian bias, economic underdevelopment, and a range of other political, economic and social issues that provide the ideal environment for radical ideas to take root.
Another critical element in the campaign against returning foreign fighters will be greater coordination between international intelligence and border control agencies, including between those agencies that do not have a well-established tradition of cooperation. This is key to the international community’s ability to understand and map the membership of foreign fighter networks and disrupt them before they become too well established. This will require effective liaison between countries and agencies so that foreign fighter intelligence does not fall into the jurisdictional and legislative cracks between states and agencies. Turkey should be a key focus of efforts to strengthen cooperation, even more so after the coup, as purges may have degraded the country’s border control capability. Turkey should be provided with the technical and intelligence resources to increase its ability to track and screen as many returnees from Syria and Iraq as possible. Similarly, there should be a greater intelligence and enforcement focus on personal recruiting networks — many of which are known — within the countries that are the sources of the greatest number of foreign fighters.
Establishing international intelligence coordination on this issue will be as much of a diplomatic effort as a technical one. Addressing the foreign fighter problem will, for example, require countries to enact necessary legislation so that foreign fighters can be detained, interrogated, charged and imprisoned to remove the threat and add to the broader intelligence picture. While the United Nations has recognised the need for member states to enact such legislation, progress has not been good. Only one-third of the 77 states identified as ‘most affected’ by the foreign fighter threat have updated their legislation in accordance with a UN resolution, while only half have developed and implemented prosecution, rehabilitation, and reintegration strategies for returnees.
The international community should also establish a foreign fighters’ working group under UN auspices, perhaps as a dedicated sub-grouping within the UN Counter-Terrorism Committee. This will allow for a greater focus on this issue and help to promote the sharing of information regarding the identities and affiliations of fighters from proscribed terrorist organisations in all theatres. This must also include the participation of Russia and Iran, both of which will have access to significant amounts of data that they should be encouraged to share. Regional foreign fighter sub-groupings should also be established to allow countries to focus on the areas of most immediate concern to them. These sub-groupings could develop new information sharing and intelligence exchange protocols to allow for easier transmission of intelligence between regional states.
Apart from their appalling human cost, the conflicts in Syria and Iraq have created a number of disastrous legacies. Chief among them has been the generation of a new cohort of jihadist fighters from around the world. Those fighters are now starting to leave those conflicts, a process that will probably accelerate in the coming months and years, taking with them the lethal skills and connections forged in Syria and Iraq. Islamic State may be under increasing military pressure, but it is clear that it is preparing for the day after the collapse of the caliphate. But even those foreign fighters who leave Islamic State disillusioned will remain a threat to global security because of the skills and contacts that they now possess.
This diffusion of terrorist expertise will pose problems for security services in both Muslim and non-Muslim countries for years to come. The world is not short of ungoverned or semi-governed spaces within which terrorist organisations can regroup. But the threat cannot be viewed as a purely national one, afflicting only those countries whose citizens have become foreign fighters; it is a systemic threat to all people that travel and trade. And while the international community cannot solve many of the root causes of terrorism, through closer intelligence cooperation and a more standardised legislative approach to the issue, it can start to contain the problem. Indeed, the international community is not without tools to address the problem of foreign fighters. It has dealt with the similar aftermaths of the Afghan and Balkan wars. But this will require political leaders and security officials to broaden their focus from today’s foreign fighter problems to those of the day after.
The authors would like to acknowledge and thank Catherine Hirst for valuable research assistance in preparing this paper.
 See Lauren Williams, Islamic State Propaganda and the Mainstream Media, Lowy Analysis (Sydney: Lowy Institute for International Policy, 2016), http://www.lowyinstitute.org/publications/islamic-state-propaganda-and-mainstream-media.
 Joby Warrick and Souad Mekhennet, “Inside ISIS: Quietly Preparing for the Loss of the Caliphate”, Washington Post, 12 July 2016.
 “The Obama Administration’s Strategy in the Fight Against ISIS”, Here and Now, WBUR Radio, 20 November 2015, http://www.wbur.org/hereandnow/2015/11/20/us-strategy-isis.
 Sarah Almukhtar, Tim Wallace and Derek Watkins, “ISIS Has Lost Many of theKey Places It Once Controlled”, The New York Times, updated 3 July 2016.
 Pol O Gradaigh, “Islamic State Pushed Back from Syrian Border after Three-year Presence”, Sydney Morning Herald, 5 September 2016, http://www.smh.com.au/world/islamic-state-pushed-back-from-syrian-border-after-threeyear-presence-20160904-gr8mxi.html.
 Columb Strack, “Islamic State Loses 22 per cent of Territory”, IHS Jane’s 360, 16 March 2016, http://www.janes.com/article/58831/islamic-state-loses-22-per-cent-of-territory.
 Aymenn Al-Tamimi, “A Caliphate Under Strain: The Documentary Evidence”, CTC Sentinel 9, Issue 4 (2016), 1–8, https://www.ctc.usma.edu/posts/a-caliphate-under-strain-the-documentary-evidence.
 “Is the Number of Foreign Fighters Entering Syria Really Plummeting?”, Newsweek, 28 April 2016, http://www.newsweek.com/isis-foreign-fighters-90-percent-iraq-syria-decreasing-general-claim-453741.
 Thomas Gibbons-Neff, “Number of Foreign Fighters Entering Iraq and Syria Drops by 90 per cent, Pentagon Says”, Washington Post, 26 April 2016, https://www.washingtonpost.com/news/checkpoint/wp/2016/04/26/number-of-foreign-fighters-entering-iraq-and-syria-drops-by-90-percent-pentagon-says/.
 Mara Revkin and Ahmad Mhidi, “Quitting ISIS”, Foreign Affairs, 1 May 2016.
 Matt Bradley, “Rift Grows in Islamic State between Foreign, Local Fighters”, The Wall Street Journal, 25 March 2016, http://www.wsj.com/articles/rift-grows-in-islamic-state-between-foreign-local-fighters-1458930063.
 Al Adnani al Shami, audio message, “Those Who Live in Faith Would Live with Evidence”, accessed 1 June 2016, http://jihadology.net/2016/05/21/new-audio-message-from-the-islamic-states-shaykh-abu-muḥammad-al-adnani-al-shami-and-those-who-lived-in-faith-would-live-upon-evidence/.
 Cole Buznel, “The Islamic State of Decline: Anticipating the Paper Caliphate”, Jihadica (blog), 15 June 2016, http://www.jihadica.com/the-islamic-state-of-decline/.
 James R Clapper, “Worldwide Threat Assessment of the US Intelligence Community”, Statement for the Record, Senate Armed Services Committee, 9 February 2016, 5, http://www.armed-services.senate.gov/imo/media/doc/Clapper_02-09-16.pdf.
 “Second and Third Informal Briefings Conclude Series of Regionally Focused Dialogues on FTF Threat”, Security Council Counter-Terrorism Committee, last updated 25 July 2016, http://www.un.org/en/sc/ctc/news/2016-07-25_CTED_Informal_Briefings_FTF.html.
 Patrick Zengerle and Jonathan Landay, “CIA Director Says Islamic State Still Serious Threat”, Reuters, 16 June 2016, http://www.reuters.com/article/us-mideast-crisis-fighters-idUSKCN0Z21ST.
 “Nusra Leader: No End to Conflict with ISIL in Syria”, Al Jazeera, 4 June 2015, http://www.aljazeera.com/news/2015/06/nusra-leader-conflict-isil-syria-150604021024858.html%3E.
 Jeff Seldin, “Al-Qaida’s Syria Affiliate Reemerges”, Voice of America, 27 August 2015, http://www.voanews.com/content/with-is-in-coalition-crosshairs-al-qaida-syria-affiliate-reemerges/2935207.html; Charles Lister, Profiling Jabhat al-Nusra, Analysis Paper No 24, The Brookings Project on US Relations with the Islamic World (Washington DC: Brookings Institution, July 2016), https://www.brookings.edu/wp-content/uploads/2016/07/Brookings-Analysis-Paper_Charles-Lister_Web.pdf.
 Mary Anne Weaver, “Her Majesty’s Jihadists”, The New York Times Magazine, 14 April 2015, http://www.nytimes.com/2015/04/19/magazine/her-majestys-jihadists.html?_r=0.
 Vish Sakthivel, “Weathering Morocco's Syria Returnees”, The Washington Institute, Policy Watch 2148, 25 September 2013, http://www.washingtoninstitute.org/policy-analysis/view/weathering-moroccos-syria-returnees.
 Hazem al-Amin, “Who is the ‘Typical” Tunisian Jihadist?”, Al Monitor, Kamal Fayad translator, 3 November 2014, http://www.al-monitor.com/pulse/security/2014/11/tunisian-jihadis-profile-fighting-syria.html.
 Henry Johnson, “Kurdish Fighters: We’d Really Appreciate if You Came to Syria to Help Fight ISIS”, Foreign Policy, 17 September 2015, http://foreignpolicy.com/2015/09/17/kurdish-fighters-wed-really-appreciate-if-you-came-to-syria-to-help-fight-isis/.
 Hardin Lang and Muath Al Wari, “The Flow of Foreign Fighters to the Islamic State: Assessing the Challenge and the Response”, Center for American Progress Report, March 2016, https://cdn.americanprogress.org/wp-content/uploads/2016/03/17132821/ForeignFighters-report.pdf.
 Amber Atteridge, “Foreign Fighters Post Conflict: Assessing the Impact of Arab Afghans and Syrian-Iraqi Fighters on Global Security”, International Institute for Counter-Terrorism, Herzliya, Israel, Spring 2016, 11.
 Lorenzo Vidino, “The Arab Foreign Fighters and the Sacralization of the Chechen Conflict”, al Nakhlah, Spring 2006, 1.
 Thomas Hegghammer, “The Rise of Muslim Foreign Fighters: Islam and the Globalization of Jihad”, International Security 35, No 3 (2010/11), 53–94, http://belfercenter.ksg.harvard.edu/files/The_Rise_of_Muslim_Foreign_Fighters.pdf.
 Andrea de Guttry, Francesca Capone and Francesca, Christophe Paulussen (eds), Foreign Fighters under International Law and Beyond (The Hague, Netherlands: Asser Press, 2016), 23.
 Aaron Y Zelin, “Foreign Fighter Motivations”, statement submitted for the conference “Taking the Fight to ISIL: Operationalizing CT Lines of Effort against the Islamic State Group”, Washington Institute for Near East Policy, 2 February 2015, https://www.washingtoninstitute.org/uploads/Documents/other/ZelinStatement20150202.pdf; Isabelle Duyvesteyn and Bram Peeters, “Fickle Foreign Fighters? A Cross-Case Analysis of Seven Muslim Foreign Fighter Mobilisations (1980–2015)”, ICCT Research Paper, October 2015, http://icct.nl/wp-content/uploads/2015/10/ICCT-Duyvesteyn-Peeters-Fickle-Foreign-Fighters-October2015.pdf.
 Lang and Wari, “The Flow of Foreign Fighters to the Islamic State: Assessing the Challenge and the Response”.
 Jennifer Mustapha, “The Mujahideen in Bosnia: The Foreign Fighter as Cosmopolitan Citizen and/or Terrorist”, Citizenship Studies 17, Issue 6–7 (2013), 747.
 Wissam Abdallah, “Ahrar al-Sham Takes Battle against IS to YouTube”, Joelle El-Khoury translator, Al Monitor, 21 August 2015, http://www.al-monitor.com/pulse/security/2015/08/syria-ahrar-al-sham-secrets-islamic-state.html.
 Buznel, “Islamic State of Decline: Anticipating the Paper Caliphate”.
 Tamimi, “A Caliphate under Strain: The Documentary Evidence”.
 Lister, Profiling Jabhat al-Nusra.
 Rukmini Callimachi, “How ISIS Built the Machinery of Terror under Europe’s Gaze”, The New York Times, 29 March 2016, http://www.nytimes.com/2016/03/29/world/europe/isis-attacks-paris-brussels.html?_r=0.
 Andrew Zammit, “List of Alleged Violent Plots in Europe Involving Syria Returnees”, The Murphy Raid (blog), 29 June 2014, https://andrewzammit.org/2014/06/29/list-of-alleged-violent-plots-in-europe-involving-syria-returnees/.
 Richard Barrett, “The Islamic State Goes Global”, CTC Sentinel 8, Issue 11 (November/December 2015).
 Michael Weiss, “Confessions of an ISIS Spy”, Daily Beast, 16 November 2015, http://www.thedailybeast.com/articles/2015/11/15/confessions-of-an-isis-spy.html.
 Callimachi, “How ISIS Built the Machinery of Terror under Europe’s Gaze.
 Rukimi Callimachi, “How a Secretive Branch of ISIS Built a Global Network of Killers”, The New York Times, 3 August 2016, http://www.nytimes.com/2016/08/04/world/middleeast/isis-german-recruit-interview.html?_r=0.
 Jason Pack, “ISIS in Action”, Eyes on Libya (blog), 11 July 2016, http://eyeonisisinlibya.com/isis-in-action/action-11-july-2016/.
 “Statement by Director Brennan as Prepared for Delivery before the Senate Select Committee on Intelligence”, 16 June 2016, https://www.cia.gov/news-information/speeches-testimony/2016-speeches-testimony/statement-by-director-brennan-as-prepared-for-delivery-before-ssci.html.
 Kate Lamb, “A Bunch of Amateurs? Indonesia’s Homegrown Jihadis Ridicule ISIS after Jakarta Attack”, The Guardian, 11 February 2016, https://www.theguardian.com/world/2016/feb/11/indonesia-homegrown-jihadis-lethal-cocktail-terror-isis-jakarta.
 “Disunity among Indonesian ISIS Supporters and the Risk of More Violence”, Institute for Policy Analysis of Conflict Report No 25, 1 February 2016, 1.
 Yenni Kwok, “ISIS Has Launched a Newspaper to Recruit Southeast Asian Fighters”, Time, 11 July 2016, http://time.com/4400505/isis-newspaper-malay-southeast-asia-al-fatihin/?xid=tcoshare.
 Akul Yunus, “IS Releases Video to Recruit Asians”, The Star, 24 June 2016, http://www.thestar.com.my/news/nation/2016/06/24/is-releases-video-to-recruit-asians-terror-group-setting-up-base-in-philippines/.
 Atteridge, “Foreign Fighters Post Conflict: Assessing the Impact of Arab Afghans and Syrian-Iraqi Foreign Fighters on Global Security”, 25.
 Kimiko de Freytas-Tamura, “ISIS Defectors Reveal Disillusionment”, The New York Times, 20 September 2015, http://www.nytimes.com/2015/09/21/world/europe/isis-defectors-reveal-disillusionment.html?_r=0.
 John Horgan, “What Makes a Terrorist Stop Being a Terrorist”, The Conversation, 18 November 2014, https://theconversation.com/what-makes-a-terrorist-stop-being-a-terrorist-33119.
 Mary Beth Altier, Christian Thoroughgood and John Horgan, “Turning Away from Terrorism: Lessons from Psychology, Criminology, and Sociology”, Journal of Peace Research 51, No 5 (2014), 647–661.
 Peter Neumann, “Victims, Perpetrators, Assets: The Narratives of Islamic State Defectors”, The International Centre for the Study of Radicalisation and Political Violence (London: King’s College, 2015), 7.
 Sidney Jones, “Santoso Dead: Now for the Next Chapter”, The Interpreter, 21 July 2016, http://www.lowyinterpreter.org/post/2016/07/21/Santoso-dead-Now-for-the-next-chapter.aspx.
 Discussions with Lebanese security authorities, Beirut, 2015–2016.
 Barbara Opall-Rome, “Raytheon–Jordan Border Defense against Isis Enters Final Phase”, Defense News, 26 May 2015, http://www.defensenews.com/story/defense/international/mideast-africa/2016/05/26/raytheon-jordan-border-defense-isis/84962218/.
 Jessica Eggert, “The US State Department Posts up to $5 Million Reward for Abu-Muhammad al-Shimali”, News.Mic, 19 November 2015, https://mic.com/articles/128903/the-u-s-department-of-state-posts-up-to-5-million-reward-for-abu-muhammad-al-shimali#.gRN9JIiFS.
 Mehul Srivastava, Laura Pitel and Geoff Dyer, “Purge of Turkish Security Forces Threatens to Disrupt Isis Fight”, Financial Times, 21 July 2016, http://www.ft.com/cms/s/0/740e1ce4-4e96-11e6-8172-e39ecd3b86fc.html#axzz4HML4gf88.
 Turkish authorities, for example, passed on intelligence regarding one of the Brussells bombers; however, it was not acted on in time: Shawn Price, Andrew Pestano and Doug Ware, “Six Arrested in Raids in Brussels; Officials Regret Not Acting on Earlier Warning”, United Press International, 24 Match 2016, http://www.upi.com/Top_News/World-News/2016/03/24/Six-arrested-in-raids-in-Brussels-officials-regret-not-acting-on-earlier-warning/4731458814196/.
 Discussions with Western intelligence and diplomatic officials.
 Dominique Soguel and Aya Batrawy, “Turkey Tightens Jihadist Highway Near Syria Border, Pressuring ISIS”, Haaretz, 6 July 2016, http://www.haaretz.com/middle-east-news/turkey/1.729255.
 Turkey has no extradition treaty with Saudi Arabia, one of the largest source countries for foreign fighters: see Republic of Turkey, Directorate General for International Law and Foreign Relations, “Legal Grounds for Extradition”, http://www.uhdigm.adalet.gov.tr/english/Extradition_Of_The_Criminals_2.html.
 Vidino, “The Arab Foreign Fighters and the Sacralisation of the Chechen Conflict”, 2.
 Thomas Hegghammer, “Should I Stay or Should I Go? Explaining Variation in Western Jihadists’ Choice between Domestic and Foreign Fighting”, American Political Science Review 107, Issue 1 (2013), 1–15, http://hegghammer.com/_files/Hegghammer_-_Should_I_stay_or_should_I_go.pdf.
 United Nations Security Council, “Report of the Secretary-General on the Threat Posed by ISIL (Da’esh) to International Peace and Security and the Range of United Nations Efforts in Support of Member States in Countering the Threat”, S/2016/501, 31 May 2016, 12.
<a id="Appendix" name="Appendix"></a>Appendix A: Oaths of allegiance to Islamic State
Islamic State/al-Qaeda affiliations as at June 2016
Notes to table
[i] “Islamic State’s 43 Global Affiliates Interactive World Map”, Intel Center, http://intelcenter.com/maps/is-affiliates-map.html#gs.rPLKKlE; Caleb Weiss, “Philippines-based Jihadist Groups Pledge Allegiance to the Islamic State”, The Long War Journal, 14 February 2016, http://www.longwarjournal.org/archives/2016/02/philippines-based-jihadist-groups-pledge-allegiance-to-the-islamic-state.php.
[ii] Jantzen W Garnett, “Is ISIS Expanding into Egypt?”, Institute for the Study of War, 27 October 2014, http://www.understandingwar.org/backgrounder/isis-expanding-egypt.
[iii] Jared Ferris, “Desknote: ISIS Signals Tunisian Presence with Bardo Museum Attack”, AEI Critical Threats, 20 March 2015, http://www.criticalthreats.org/west-africa/ferris-bardo-museum-attack-march-20-2015.
[iv] Simon Speakman Cordall, “Tunisian Terror Cell Promises More Bloodshed in New Video”, Newsweek, 29 June 2015, http://europe.newsweek.com/tunisian-terror-cell-promise-more-bloodshed-new-video-329480: “On 18 May hitherto unknown Tunisian terrorist cell, the Mujahideen Tunisia Kairouan, declared both its presence within Tunisia and fealty to Isis.”
[v] “Islamic State in Yemen/Wilayat Sana’a”, GlobalSecurity.org, http://www.globalsecurity.org/military/world/para/wilayat-sanaa.htm.
[vi] “Gulf of Aden Security Review — September 4, 2014”, AEI Critical Threats, http://www.criticalthreats.org/gulf-aden-security-review/gulf-aden-security-review-september-4-2014#_edn1.
[vii] No information found on this group other than their pledge of allegiance. Possibly a new organisation that has emerged: “Islamic State’s 43 Global Affiliates Interactive World Map”, Intel Center, http://intelcenter.com/maps/is-affiliates-map.html#gs.rPLKKlE.
[viii] Balasubramaniyan Viswanathan, “Ansar-ut Tawhid: Seizing the Reins from Indian Mujahideen in India?”, Geopolitical Monitor, 4 October 2015, http://www.geopoliticalmonitor.com/ansar-ut-tawhid-seizing-the-reins-from-indian-mujahideen-in-india/.
[ix] Formerly an ally and al-Qaeda funding recipient (although would not describe the group as an affiliate). Bruce Pannier, “What Next for the Islamic Movement of Uzbekistan?”, Qishloq Ovozi (blog), 23 August 2015, http://www.rferl.org/content/qishloq-ovozi-imu-ghazi-uzbekistan-pakistan/27204379.html; “Islamic Movement of Uzbekistan (IMU)”, The Mackenzie Institute, 1 January 2016, http://mackenzieinstitute.com/islamic-movement-uzbekistan-imu/.
[x] Had alliances with various Syrian rebel groups, including at times with al-Nusra; however, not an al-Qaeda affiliate. Aymenn Jawad Al-Tamimi, “Liwa Shuhada’ al-Yarmouk: History and Analysis”, Syria Comment,
18 September 2015, http://www.joshualandis.com/blog/liwa-shuhada-al-yarmouk-history-and-analysis/.
[xi] Katibat al-Imam Bukhari is an Uzbek jihadist group in Syria; coordinates with Jabhat Fatah al-Sham and other rebel groups (not an affiliate of al-Qaeda so faction that pledged allegiance to Islamic State not listed as an al-Qaeda defector). Joanna Paraszczuk, “Central Asian Militants in Syria Pledge Allegiance to IS”, Under the Black Flag (blog), 30 October 2014, http://www.rferl.org/content/under-black-flag-central-asia-militants-allegiance/26666098.html; “Imam Bukhari Jamaat”, Terrorism Research & Analysis Consortium, http://www.trackingterrorism.org/group/imam-bukhari-jamaat.
[xii] No links to al-Qaeda found. Karl Morand, “Jihadism in the Land of the Pharaohs”, Jihadology (podcast), 26 October 2015, http://jihadology.net/category/other-groups/jamaat-an%E1%B9%A3ar-bayt-al-maqdis/.
[xiii] Hans Krech, “How Stable Is the Caliphate of the Islamic State?”, ENDC Proceedings 19/2014 (2014), 148–163, http://www.ksk.edu.ee/wp-content/uploads/2014/12/KVUOA_Toimetised_19_08_krech.pdf.
[xiv] Supportive of Jabhat Fatah al-Sham, although no direct links found. “Islamic State’s 43 Global Affiliates Interactive World Map”, Intel Center, http://intelcenter.com/maps/is-affiliates-map.html#gs.rPLKKlE; “Jihad and Terrorism Threat Monitor (JTTM) Weekend Summary”, The Middle East Media Research Institute, 15 December 2012, http://www.memri.org/report/en/print6876.htm.
[xv] Aaron Y Zelin, “The Islamic State’s First Colony in Libya”, The Washington Institute, PolicyWatch 2325,
10 October 2014, http://www.washingtoninstitute.org/policy-analysis/view/the-islamic-states-first-colony-in-libya.
[xvi] Formed by former JAT commander Santoso in 2011; tried to forge links with al-Qaeda prior to baya to al-Baghdadi, but no confirmation that their attempts were successful found. “Mujahidin Indonesia Timur (MIT)”, Terrorism Research & Analysis Consortium, http://www.trackingterrorism.org/group/mujahidin-indonesia-timur-mit; Greg Fealy and John Funston, “Indonesian and Malaysian Support for the Islamic State: Final Report”, United States Agency for International Development, 6 January 2016, http://www.globalsecurity.org/military/library/report/2016/PBAAD863.pdf.
[xvii] Indonesian; offshoot of JI; although Abu Bakar Bashir is the founder, no evidence of direct links to al-Qaeda found. Katie Zavadski, “ISIS Now Has a Network of Military Affiliates in 11 Countries Around the World”, New York Magazine, 23 November 2014, http://nymag.com/daily/intelligencer/2014/11/isis-now-has-military-allies-in-11-countries.html.
[xviii] Don Rassler, “Situating the Emergence of the Islamic State of Khorasan”, CTC Sentinel 8, Issue 3 (March 2015), https://www.ctc.usma.edu/posts/situating-the-emergence-of-the-islamic-state-of-khorasan.
[xix] Joanna Paraszczuk, “Central Asian Militants in Syria Pledge Allegiance to IS”, Under the Black Flag (blog), 6 September 2016, http://www.rferl.org/content/under-black-flag-central-asia-militants-allegiance/26666098.html.
[xx] Some members have not followed the leadership in pledging loyalty to Islamic State; Ansar al-Islam have received support from al-Qaeda in the past, although would not describe the group as an al-Qaeda affiliate. Abdallah Suleiman Ali, “IS Disciplines Some Emirs to Avoid Losing Base”, Al Monitor, 2 September 2014, http://www.al-monitor.com/pulse/security/2014/09/is-takfiri-caliphate.html#; Thomas Joscelyn, “Ansar al Islam Claims Attacks against Iraqi Military, Police”, The Long War Journal, 20 June 2014, http://www.longwarjournal.org/archives/2014/06/_operating_in_iraq_w.php.
[xxi] Three battalions (Ansar al Sharia, Marakah al Ansar, Jund al Tawhid) and leader Isnilon Hapilon pledged baya to Islamic State; unclear how many other members of the group have also pledged. Caleb Weiss, “Abu Sayyaf Group Battalion Defects to Islamic State”, Threat Matrix (blog), 22 March 2016, http://www.longwarjournal.org/archives/2016/03/abu-sayyaf-group-battalion-defects-to-islamic-state.php.
[xxii] “Nigeria’s Boko Haram Pledges Allegiance to Islamic State”, BBC News, 7 March 2015, http://www.bbc.com/news/world-africa-31784538.
[xxiii] Jantzen W Garnett, “Is ISIS Expanding into Egypt?”, Institute for the Study of War, 27 October 2014, http://www.understandingwar.org/backgrounder/isis-expanding-egypt.
[xxv] “Former AQIM Division in Algeria Pledges Allegiance to IS Leader”, SITE Intelligence Group, 25 July 2015, https://news.siteintelgroup.com/Jihadist-News/former-aqim-division-in-algeria-pledges-allegiance-to-is-leader.html.
[xxvi] Contention as to whether or not the whole battalion defected to Islamic State — AQIM claims only ten members pledged baya to Islamic State. Caleb Weiss, “AQIM Battalion Claims ‘Fewer Than 10’ Members Defected to Islamic State”, The Long War Journal, 5 September 2015, http://www.longwarjournal.org/tags/al-ansar-battalion.
[xxvii] Adam Ereli, Deputy Spokesman, “Designation of Dhamat Houmet Daawa Salafia under Executive Order 13224”, US Department of State Press Statement, 20 October 2003, http://2001-2009.state.gov/r/pa/prs/ps/2003/25413.htm; “The Development in Algeria in the Shade of the Arabic Spring, and its Consequences on Migration (Public version)”, Report from a Swedish-Swiss fact-finding mission to Algeria, June 11–16, 2011, Swiss Federal Department of Justice and Police and Swedish Migration Board, 20 January 2012, https://www.sem.admin.ch/dam/data/sem/internationales/herkunftslaender/afrika/dza/DZA-ber-factfindingmission-e.pdf.
[xxviii] Carlotta Gall, Declan Walsh and Douglas Schorzman, “How the Pakistani Taliban Became a Deadly Force”, The New York Times, 16 December 2014, http://www.nytimes.com/2014/12/17/world/asia/how-the-pakistani-taliban-became-a-deadly-force.html?_r=0.
[xxix] Abu Dujana Al-Afghani led by Sheikh Abu Yazid Abd al-Qahir Khorasani. Hans Krech, “How Stable Is the Caliphate of the Islamic State?”, ENDC Proceedings 19/2014 (2014), 148–163, http://www.ksk.edu.ee/wp-content/uploads/2014/12/KVUOA_Toimetised_19_08_krech.pdf.
[xxx] Thomas Joscelyn, “Amid Defections, Islamic Caucasus Emirate Publicly Recognizes New Leader”, The Long War Journal, 6 July 2015, http://www.longwarjournal.org/archives/2015/07/amid-defections-islamic-caucasus-emirate-publicly-recognizes-new-leader.php.
[xxxii] “Islamic State’s 43 Global Affiliates Interactive World Map”, Intel Center, http://intelcenter.com/maps/is-affiliates-map.html#gs.rPLKKlE.
[xxxiii] Formerly known as Jabhat al-Nusra, Jabhat Fatah ash-Sham has publicly proclaimed it no longer takes direction from al-Qaeda. It is widely believed that this is for its own political purposes in order to become more acceptable to other Syrian jihadist groups and regional states. It continued to praise al-Qaeda and Osama bin Laden even while proclaiming its independence.
[xxxiv] Although Abu Bakar Bashir has pledged baya to al-Baghdadi, what is left of JI support al-Nusra. Greg Fealy and John Funston, “Indonesian and Malaysian Support for the Islamic State: Final Report”, United States Agency for International Development, 6 January 2016, http://www.globalsecurity.org/military/library/report/2016/PBAAD863.pdf.
[xxxv] Created by former JAT members who split after leader Abu Bakar Bashir’s baya to Islamic State; see caliphate as illegitimate, and claim to be part of al-Qaeda’s network. Bill Roggio, “Islamic State Launches Suicide Assault in Indonesia’s Capital”, The Long War Journal, 14 January 2016, http://www.longwarjournal.org/archives/2016/01/islamic-state-launches-suicide-assault-in-indonesias-capital.php.
[xxxvi] “Al Shabaab”, Mapping Militant Organizations, updated 20 February 2016, https://web.stanford.edu/group/mappingmilitants/cgi-bin/groups/view/61.
[xxxvii] “Shared Goals for Pakistan’s Militants”, General David H Petraeus interviewed by Greg Bruno and Jayshree Bajoria, 6 May 2010, http://www.cfr.org/pakistan/shared-goals-pakistans-militants/p22064; General David H Petraeus; Thomas Joscelyn, “Pakistani Taliban Spokesman Says Reports of Joining Islamic State are ‘Lies’”, The Long War Journal, 10 September 2015, http://www.longwarjournal.org/archives/2015/09/pakistani-taliban-spokesman-says-reports-of-joining-islamic-state-are-lies.php.
[xxxviii] Long history of ties and support between LET and al-Qaeda; LET likely has links to the newly formed AQIS. Bill Roggio, “Al Qaeda in the Indian Subcontinent Incorporates Regional Jihadist Groups”, The Long War Journal, 5 September 2014, http://www.longwarjournal.org/archives/2014/09/analysis_al_qaeda_in.php; “Lashkar-e-Taiba”, Mapping Militant Organizations, updated 30 January 2016, https://web.stanford.edu/group/mappingmilitants/cgi-bin/groups/view/79.
[xxxix] Bill Roggio, “Chechen Commander in Syria Pledges to Islamic Caucasus Emirate”, The Long War Journal, 10 July 2015, http://www.longwarjournal.org/archives/2015/07/chechen-commander-in-syria-pledges-to-islamic-caucasus-emirates.php.
[xl] Links, not allegiance; likely an ally, rather than an affiliate. Thomas Joscelyn, “In Dabiq Magazine, Islamic State Complains about Jihadist Rivals in Libya”, The Long War Journal, 13 September 2015, http://www.longwarjournal.org/archives/2015/09/in-dabiq-magazine-islamic-state-complains-about-jihadist-rivals-in-libya.php; Paul Cruickshank, Nic Robertson, Tim Lister and Jomana Karadsheh, “ISIS Comes to Libya”, CNN, 18 November 2014, http://edition.cnn.com/2014/11/18/world/isis-libya/.