Despite suffering territorial defeat in Baghouz, Syria, in March 2019 at the hands of the Kurdish-led Syrian Democratic Forces (SDF) with support from the US-led Operation Inherent Resolve mission, the Islamic State in Iraq and Syria (ISIS) continues to covertly operate and remains a potent threat capable of carrying out attacks. ISIS prisons and camps guarded by the SDF also remain incredibly volatile and have been the source of persistent security problems.
Previously, the October 2019 Turkish military invasion of SDF-controlled territory in northern Syria saw a restive population of imprisoned ISIS fighters and detainees respond to regional instability with riots and escape attempts. Many of the SDF personnel guarding had been redeployed to fight Turkish-backed forces, prioritising territorial defence, providing a perfect opportunity for the group to exploit the resultant insecurity. The continued threat posed by ISIS prisoners was more recently highlighted by the January 2022 al-Sina prison uprising and attack, which saw a 10-day long battle with SDF fighters and prison guards.
Turkish President Recep Tayyip Erdogan has recently threatened to launch another military operation into SDF-controlled territory in northern Syria, targeting Kurdish "terrorists" and capturing the towns of Tel Rifaat and Manbij to the west of the Euphrates River. The Kurdish YPG (Yekîneyên Parastina Gel-People's Protection Units) forms the backbone of the SDF, whom the US has supported with airstrikes in the fight against ISIS since 2014. Turkey considers the YPG an extension of the PKK (Partiya Karkerên Kurdistan-Kurdistan Workers Party), a group it recognises as a terrorist organisation.
Another Turkish invasion could have significant implications for both local and international security. SDF fighters could be drawn away from ongoing operations against ISIS cells and the guarding of ISIS prisoners to fight against Turkish forces, creating an environment conducive for ISIS stepping up attacks in Syria or organising prison breakouts. Escapees from understaffed ISIS prisons and camps could also create international security threats through bolstering the ranks of ISIS networks or carrying out terrorist attacks overseas. Long-term impacts could result in disrupting and weakening the SDF-US alliance in Syria, undermining what has been a highly effective counter-terrorism partnership. This perspective will examine and expand on each of these points.
The status of ISIS detainees in Syria
The most immediate risk from another Turkish operation in Syria is from ISIS prisoners and their supporters held in camps across northern Syria by the SDF. Following the 2019 defeat of ISIS, the poorly-resourced SDF has been left to secure and deal with nearly 12,000 ISIS fighters kept in overcrowded makeshift prisons and nearly 60,000 women and children affiliated with the group at al-Hol camp. The prisons and camps have consistently been a source of security issues, including major riots and escape attempts, and have been described by the US as posing a "significant risk" to anti-ISIS coalition forces in Syria. A military operation launched by Turkey against the SDF risks causing a reduction in manpower available for guarding the facilities, with fighters likely to prioritise resisting a Turkish operation.
During the October 2019 U.S forces withdrawal and Turkish invasion, the SDF redeployed many of their fighters from guarding prisons across Syria to battle Turkish-backed forces, with a guard force of at least 700 at Ain Issa camp reportedly reduced to as few as 60-70. As many as 850 ISIS detainees were said to have escaped from Ain Issa after Turkish bombs struck the camp's vicinity. While many were later recaptured, the US Special Representative for Syria claimed that at least 100 ISIS fighters were still unaccounted for. Incidents of civil disobedience and attacks on guards, were also reported at other similarly understaffed prison facilities.
Furthermore, the SDF lacks the capacity to sustain security long-term, with makeshift prisons consisting of former school buildings and prison wings effectively run internally by the ISIS inmates themselves. There has continued to be further major riots at ISIS prisons under SDF control long after the 2019 invasion. In al-Hol camp, scores of murders are regularly committed, where extremists enforce ISIS laws, attack those co-operating with the guards, and force out aid organisations. Weapons are regularly smuggled into the camp, while hundreds have escaped, and young boys are regularly smuggled out to ISIS-run desert training camps.
In January 2022, 200 ISIS fighters attacked al-Sina prison in Hassakeh in a mass breakout attempt initiated by a truck bomb. Between 30-300 inmates escaped, and an estimated 500 were killed in 10 days of fighting which spread to nearby neighbourhoods and required coalition airstrikes and special forces to quell. The uprising demonstrated ISIS had been steadily reconsolidating itself while inmates had the capacity to coordinate complex operations with those outside the prison. Following the al-Sina attack, many prisoners were moved to a more secure facility, but the threat posed by ISIS detainees remains, particularly in the al-Hol facility, which saw armed clashes with guards two months later, sparking fears of a similar attack.
A mass breakout from of one of the facilities could have significant implications for local and international security. Escaped inmates or affiliates could easily bolster forces waging an insurgency in the region. Some could also make use of well-established smuggling networks to cross international borders, where they could potentially conduct attacks or join other ISIS networks. Thousands of those in captivity are foreign citizens. The continued risk of their possible escape should also highlight more than ever the urgent need for their repatriation. As long as they are still held in northern Syria, they will continue to remain a security concern.
ISIS: A resilient threat
A Turkish invasion could also be detrimental to ongoing joint US-SDF counter-terrorism operations, with an SDF spokesperson claiming they intend to pause operations against ISIS if an invasion occurs. ISIS has also been steadily rebuilding their capabilities over the last three years and has a track record of effectively exploiting opportunities offered by fighting among their enemies. The Turkish invasion of Afrin in 2018 saw ISIS rebuild briefly on the battlefield as SDF efforts lost momentum. The 2019 invasion saw a similar disruption, as SDF fighters were once again pulled away from operations against ISIS to battle Turkish-backed forces in the north, with ISIS propaganda declaring an increase of attacks during that same period (although Operation Inherent Resolve officials later pushed back against their claims). However, ISIS’ capabilities today certainly differ from those of 2019, when the group had just suffered their devastating territorial defeat and needed time to rebuild, although the number of attacks remains relatively low.
ISIS have since been able to expand their insurgency and low-intensity clandestine operations in Central Syria throughout 2020 and have established strongholds and sanctuaries across the country, including in the Eastern Syrian desert, as well as SDF-controlled Deir ez-Zor. Regular activity from sleeper cells has been reported in areas under SDF control throughout 2020 and 2021, with the deterioration of security around Deir ez-Zor, and areas around Shaddadi. While attacks are relatively low in number, they remain a key constant security concern in SDF-controlled areas and require constant pressure, with regular SDF raids supported by the anti-ISIS coalition necessary for eliminating sleeper cells and rounding up leaders.
Exacerbating humanitarian concerns and conflict dynamics
A Turkish invasion could also create further negative impacts in many other unpredictable ways, including humanitarian as previous Turkish military operations in Syria have exacerbated humanitarian crises in the country. Another invasion could also cause mass displacement as refugees flee from the fighting into areas of SDF control, straining already fraught resources and hindering the SDF's ability to maintain security in regions under their control.
As the coordination efforts seen in the January 2022 al-Sina attack demonstrate, ISIS remain a resilient threat and may now have a stronger capacity to launch larger operations or increase the momentum of their attacks. The historical ability of the group to effectively exploit grievances between enemies and the risk of a security vacuum caused by an overwhelmed SDF provides ample opportunities for ISIS to exploit. ISIS is arguably in a greater position of strength having reconstituted itself in rural areas and rebuilt local networks of cells, and may be better able to take advantage and intensify insurgency efforts than previously and increase efforts to further destabilise the region.
Exploiting Geopolitical Instability
A renewed Turkish offensive could also have an impact beyond the ongoing counter-terrorism efforts on the ground - it could also have a destabilising effect on the (geo)political situation in the region. Where the Trump administration had lifted the sanctions imposed on Turkey, after Ankara had agreed to abide by a ceasefire in northern Syria under the October 22 Sochi agreement, the breach of these could lead to a new rift in bilateral relations. Consequently, this will have negative implications for the new approach taken by US President Biden, which focuses on restoring relations with Turkey and increasing cooperation in order to maintain security.
Increasing tensions between important actors involved in the counter-ISIS operations would present the group with the sought-after opportunity they need to regroup themselves. The al-Sina prison attack is a stark reminder of the threat ISIS still poses, with the counter-terrorism operations aimed at fighting the group being highly dependent on a stable geopolitical situation. Hence, the warning of US Secretary of State Antony Blinken against renewed military operations, as it would: “undermine regional stability (and) provide malign actors with opportunities to exploit instability.” The possible consequences of a scenario with such instability show when analysing the power vacuum left after the initial US withdrawal from Syria. This decision made by the US government as part of their new Middle East strategy provided ISIS with the opportunity to rebuild and re-emerge as a potent threat. In response, approximately nine hundred US troops remained, in order to deny ISIS the opportunity to develop a new safe haven in the region. The US presence has since almost fully shifted objectives towards supporting and advising the SDF on counter-terrorism operations, implying a conditions-based US mandate rather than a calendar-based one. The SDF have been spearheading operations within this counter-terrorism strategy in northern Syria thus far, proving to be an essential partner. However, a Turkish offensive towards Manbij and Tal Rifaat would pressure the SDF to divert troops away from their counter-terrorism and security operations, weakening their position.
The ability of ISIS and its affiliates to subsequently exploit possible consequences, such as geopolitical instability, is shown by the growing strength of its eastern branch, Islamic State Khorasan Province (ISIS-K), after the withdrawal of the US and its allies from Afghanistan. Where the branch was initially relatively unknown, it was able to increase its operations to attacks which killed around 400 civilians after the Taliban take-over in August 2021. Whilst the situation in Afghanistan is difficult to compare to the situation in Syria, it can serve as a warning of what could happen if ongoing counter-terrorism programmes are halted in an unstable region. A situation vulnerable to ISIS exploitation could be created, with no US capacity to fully take over counter-terrorism operations if the SDF are forced to relocate their fighting forces.
Redefining Strategic Partnerships
Despite the limited number of troops on the ground in Syria at this time, the United States does have a long history of interventions and counter-terrorism operations in the Middle-East. Many of these operations have been, and are still being, structured around cooperation with local partners such as the SDF. This can be observed in recent US-led counter-terrorism efforts which resulted in achievements such as the elimination of Abu Ibrahim al-Qurashi, also known as Hajji Abdullah, the successor to Abu Bakr al-Baghdadi as the leader of ISIS. Operations such as these are part of the lengthy US counter-terrorism tactics applied within Syria. Comparable operations take months of preparation and showcase the heavy reliance on the support of local partners such the SDF, whose support to missions such as the Hajji Abdullah strike has been described as: “essential to the mission’s success.” Cooperation with these local partners, made increasingly difficult as a result of the Turkish objectives, is therefore key for the continuation of American counter-terrorism operations within Syria.
With a high dependency on local partners and a limited force deployed in the region, unpredictable factors such as a renewed Turkish offensive, would have long-term implications for the Kurdish-American alliance and American counter-terrorism strategy as a whole. A renewed Turkish offensive into SDF-controlled territory, would leave US troops vulnerable to attacks and less capable of striking against possible ISIS targets. A preoccupied SDF would limit their intelligence capabilities, functions which have proven decisive in US strikes such as the Al-Qurashi operation. Furthermore, as the mandate of the US troops in Syria is limited to the assistance of the SDF in assuring the enduring defeat of ISIS, it would have to move troops away from possible zones of contact with Turkish troops. Where in the earlier stages of the conflict in Syria, US troops were used as deterrence against both Russia and Turkey, the primary focus of the US will now be to secure the safety of the US troops.
The withdrawal of troops would fit within the pattern of a general US withdrawal from the Middle-East, with the retreat out of Afghanistan being a looming example. However, according to recent observations it will be unlikely that a full-scale withdrawal from Syria will happen within the foreseeable future. With the consequences of the actions in Afghanistan in mind, in combination with the current proven counter-terrorism operations in the region, the US is likely to remain an active actor in Syria. The criticism in Washington after the initial plans to change the policy approaches in Syria further supports this argument.
As the US is likely to remain active in the region, a Turkish offensive would have long-term implications. One of the more probable implications is the increase of Russian activity in the regions near the planned Turkish objectives. Russia has already started to reinforce positions near Tal Rifaat, Kobani and Ain Issa, and even the Syrian regime and its Iranian militias have mobilised to reinforce positions in the region. These moves can be regarded as a response to an assertive Turkey, but with the US withholding from direct support, the SDF will be forced to look at expanding their cooperation with Russia in order to sustain their territorial control. With the main Russian criticism towards the SDF and YPG being their loyalty to the US, them opening up towards Russian assistance could shift the Russian partnerships within Syria. Increased talks between Russia and the SDF, could help Russia push the SDF into a dialogue with the Syrian government, without US input. This could strengthen Russia’s position, as they could pressure the SDF into distancing themselves from the US, with Russia becoming the dominant factor withholding the Syrian government from striking areas under SDF-control. As a result, the Russian objective of pushing back against the US-led liberal international order, could be partially met in Syria. These events would not only destabilise the US position in the region, but also impact the current counter-terrorism operations. Russia would therefore have to expand their operations from helping the Syrian government to reconquer its territory, to taking up more counter-terrorism operations. The US would then have to engage in more cooperation with Russia, despite the deteriorating relations between the two countries. The Turkish plans for northern Syria could therefore not only impact alliances on the ground, but also the counter-terrorism balance in the long run.
ISIS has proven to be a resilient foe, one which should not be underestimated. Where President Trump claimed a “100 percent” victory over the ISIS Caliphate only a couple of years ago, attacks such the Al-Sina prisonbreak show the harsh reality of the current situation in Syria.
A US-SDF coalition is currently spearheading the fight against the ISIS sleeper cells and leading the counter-terrorism operations in northern Syria. Operating with limited capabilities and a restricted mandate, these efforts are highly dependent on the continuation of the status-quo as written out in the October 22 Sochi agreements. Agreed to by both Turkey and Russia, the aim was to stabilise a fragile, but explosive country in order to prevent further escalation. Instead, infringements of these agreements at the hands of renewed Turkish assertiveness, Russian objectives, and a shift in US focus, have led to an uncertain power balance. This uncertainty might, subsequently, evolve into instability, which, as a result, could undermine counter-terrorism operations in the region.
A new Turkish assault would therefore both have short-, and long-term consequences for the geopolitical situation and the counter-ISIS operations that depend on it. Short-term consequences being that the US might have to accept an increase in Russian activity and a temporary loss of an essential counter-terrorism partner, with prisons filled with ISIS fighters becoming vulnerable targets. In the long run, these decisions could lead to an ISIS re-emergence as seen in Afghanistan, leaving Russia and Turkey to become dominant actors in newly shaped counter-terrorism strategies. Nonetheless, the Turkish plans will have far-reaching implications for the US, as they will have to deal with some hard decisions in order to maintain a foothold in the region. In order to uphold any form of effective counter-terrorism operations, opposing actors will have to find common grounds, in order to prevent ISIS from rising once more.