Turkey's Precarious Balancing Act: Managing the ISIS Threat Amid International Scrutiny

Ankara faces a complex and growing challenge in managing individuals linked to the Islamic State (ISIS), prompting international concerns over the potential for extremists to re-emerge globally. While Turkey actively conducts counter-terrorism operations, its policies regarding detained militants—particularly the repatriation of foreign fighters and the handling of domestic suspects—have led to accusations of a "revolving door" that could inadvertently facilitate the movement of radicalized individuals across borders, raising security alarms in Europe and beyond.

Turkey, strategically positioned at the crossroads of Europe and Asia and bordering conflict-ridden Syria and Iraq, has long grappled with the multifaceted threat posed by the Islamic State. The nation has experienced devastating ISIS-orchestrated attacks on its own soil, including a 2015 suicide bombing in Ankara that killed over 100 people and a 2017 New Year's Eve nightclub attack in Istanbul, underscoring the severe domestic security challenges. Concurrently, Turkey served as a significant transit route for thousands of foreign fighters joining ISIS in its heyday, with estimates suggesting between 5,000 and 9,000 Turkish citizens also traveling to ISIS-held territories. This dual reality—both a victim of and a conduit for extremism—places Ankara under intense international scrutiny regarding its counter-terrorism strategies and their broader implications for global security.

The Enduring Shadow of ISIS Within Turkey

Despite the territorial defeat of ISIS's self-proclaimed caliphate, the threat of the organization and its affiliates persists within Turkey. Turkish authorities regularly conduct extensive counter-terrorism operations, leading to thousands of arrests. In 2022, for example, Turkey reported detaining 29,751 people suspected of links to terrorist groups, including ISIS. Recent operations in late 2025 saw over 100 suspected ISIS members arrested across various provinces for allegedly plotting attacks during Christmas and New Year celebrations in Turkey and Europe. These actions highlight Ankara's ongoing commitment to disrupt ISIS networks domestically and prevent potential attacks.

However, historical analyses indicate that Turkey's approach to the ISIS threat has evolved. In the early stages of the Syrian conflict, some reports suggested a "permissive attitude" towards jihadist groups, with Turkey primarily viewing the Assad regime as the greater threat. This period saw Turkey become a "recruitment hub and transit point for ISIS." While Turkish officials have since intensified efforts against ISIS, the legacy of this initial phase and the continued presence of ISIS-linked individuals remain a significant concern. The International Crisis Group noted that thousands of Turkish citizens who joined ISIS have since returned, with the "fate of the rest [remaining] murky" after many serve brief sentences or are placed under surveillance.

Ankara's Repatriation Drive and the "Hotel" Diplomacy

A significant facet of Turkey's strategy against foreign ISIS members has been its aggressive repatriation policy. Since 2019, Ankara has declared its intention to send foreign ISIS militants held in Turkish custody back to their home countries, often despite the reluctance of those nations to accept them. Turkish Interior Minister Süleyman Soylu explicitly stated in 2019 that Turkey was "not a hotel for foreign terrorists," emphasizing that these individuals would be sent back even if their citizenships had been revoked.

Between 2015 and 2020, Turkey deported 8,143 individuals for suspected terrorism ties, and by September 2022, the number of foreign terrorist fighters (FTFs) deported since 2011 reached 9,000, representing 102 different nationalities. This policy has led to the return of individuals to European countries, the United States, and others. For instance, in November 2019, Turkey began deporting American, German, and Danish ISIS suspects, with plans for more repatriations to various European nations. While Ankara views these repatriations as a necessary measure to shift the burden of prosecuting and managing these individuals back to their countries of origin, many European nations have expressed deep reservations, fearing the security risks posed by returning radicalized individuals, especially those stripped of citizenship.

The "Revolving Door" and Exporting Militancy Concerns

The effectiveness and implications of Turkey's approach, particularly its handling of ISIS detainees, have drawn considerable international criticism, with some observers describing it as a "revolving door" policy. Critics argue that many ISIS suspects detained in Turkey face brief incarceration periods before being released or deported, often without stringent follow-up by their home countries. In February 2023, former Interior Minister Süleyman Soylu disclosed that of nearly 2,000 ISIS suspects detained in one year, more than two-thirds were released by prosecutors or courts without prosecution for terrorism offenses. Over five years, Turkey formally sent 1,126 European-origin ISIS militants back to Europe, a policy described by some as "effectively exporting militants rather than containing them."

This perceived leniency has led to international alarm, with European counterterrorism officials privately acknowledging that Turkey's practices have "repeatedly undermined their efforts to contain ISIS networks." Instances have emerged where militants, released by Turkish authorities, subsequently re-appeared in European jurisdictions, forcing costly investigations to mitigate renewed threats. A notable case involved a Tajik national arrested in Gaziantep in 2016 while attempting to join ISIS. Instead of prosecution, Turkish authorities briefly held him, released him, and allowed him to choose a destination, eventually leading him to Europe where he was later convicted for ISIS membership. Such incidents fuel concerns that Turkey's policies, while aiming to reduce its domestic burden, inadvertently contribute to the spread of extremist threats internationally.

Managing Homegrown Radicalization and Returnees

Beyond foreign fighters, Turkey faces the enduring challenge of its own citizens who joined ISIS and have since returned or been radicalized domestically. Estimates indicate that thousands of Turkish nationals went to fight for ISIS, and many have since re-entered the country. The International Crisis Group highlighted that while some have been prosecuted and jailed, many will soon be released, and others remain under surveillance, their ultimate trajectory "murky."

Ankara's strategy for these returnees largely relies on surveillance and detention, which is resource-intensive and may not be foolproof. The lack of comprehensive data on their trajectories and the absence of robust rehabilitation or de-radicalization programs raise long-term security questions. The possibility of these individuals either becoming re-radicalized, acting as sleeper cells, or influencing others remains a constant threat, both within Turkey and potentially beyond its borders if not effectively managed.

Conclusion: A Shared Security Landscape

Turkey's efforts to combat ISIS are significant, marked by ongoing operations and a firm stance against the presence of foreign fighters. However, the complexity of managing a large population of ISIS-linked individuals—both foreign and domestic—has created a delicate international dynamic. The "revolving door" policy for detainees and the often-contentious repatriation of foreign militants, while stemming from Turkey's desire to safeguard its own security and share the burden, have ignited concerns among its allies.

The core issue remains how to prevent these individuals from continuing their extremist activities. While there is no evidence to suggest a deliberate policy by Turkey to "export" its own radicalized citizens to commit attacks abroad, the consequences of its current management strategies, particularly the release and repatriation practices, are seen by some as effectively allowing militants to re-enter the global security landscape. The ongoing challenge for Turkey, and for the international community, is to find more effective, cooperative, and sustainable solutions that prevent the spread of extremism and ensure these individuals are no longer a threat, regardless of their nationality or origin.