One of the most vexing challenges faced in northeast Syria is what to do with some 10,000 ISIS fighters as well as 60,000 women and children left behind after the territorial defeat of ISIS. These individuals are detained in a network of prisons and camps run by the Syrian Democratic Forces (SDF) under the political leadership of the Syrian Democratic Council (SDC) with some financial support from the United States and other governments. However, the overcrowded and inhumane conditions in the prisons and camps – with no solution in sight – have created enormous strain on the SDF and fomented tension. This has led to prison breaks and violence within the camps, which could fuel a resurgence of ISIS.

The situation is at once a human rights emergency while also posing a threat to national security. All of the detainees are deprived of due process as they are being held without charge and without any prospects for judicial consideration of their status. Conditions violate international human rights standards and may amount to torture. Innocent children detained with their mothers are not provided any form of education and do not have even their basic needs met. Continued detention in such conditions can be a breeding ground for terrorist fighters as it radicalizes or re-radicalizes those most susceptible to indoctrination. Given the size of the problem, there is an immediate need to triage a coordinated response to different detained groups, identifying the most pressing circumstances to be addressed first.

Foreign Fighters

Repatriation of foreign fighters is the proposal most often espoused as an antidote to indefinite detention in northeast Syria. Indeed, foreign fighters are one of the most significant populations within ISIS as they are likely to be the most motivated to the cause, hardened by combat, and least likely to have ways to return to a peaceful life post-conflict. Hundreds of fighters have been repatriated to Kazakhstan, Kosovo, Russia, and Uzbekistan. However, Western States have been reluctant to repatriate their own nationals as it is domestically unpopular, there may be insufficient evidence to support convictions and a legal framework lacking prosecutable crimes, and rehabilitation efforts are perceived to have poor prospects of success. Even countries that have repatriated foreign fighters are known to have released them without trial. For example, Kazakhstan, Uzbekistan, Russia, and Tajikistan took hundreds of fighters back, but failed to investigate or prosecute (all of) them.

Women and Children

The largest group of those left behind by the crumbling of ISIS are women and children. According to the latest report by Human Rights Watch, there are 63,400 family members in two camps run by the SDF, of which 90 percent are children under the age of 12. The camp conditions are inhumane with

contaminated water, overflowing latrines, shortages of fresh food and diapers, tents leaking or catching fire, rampant disease, insufficient medical care, and almost no schooling for children or counseling for a severely traumatized population.

Many women remain hardline ISIS supporters. Some patrol the camps and enforce strict rules against other women, with reportedly 33 killings within al-Hol camp in 2020. About 8,000 are children brought to Syria from over 60 others countries or born under ISIS some of whom may be stateless. This situation fuels support for ISIS as the SDF is overwhelmed by the number of inhabitants and is unable to provide basic needs while ISIS enlists new members from al-Hol through threats or coercion. Efforts to repatriate women and children for reintegration or prosecution have also been stymied. For example, Canada was considering repatriation of a number of women and children until a public backlash following the New York Times’ Caliphate podcast, which featured a purported ISIS fighter who claimed to have returned to Canada without legal repercussions. The reporting later proved to be false but not before it forced Canada to reassess its repatriation policy. There are also concerns that to repatriate children alone means separating them from their mothers in violation of the Convention on the Rights of the Child.


Over the last two years, thousands of Syrian fighters have been granted what amount to amnesties by the SDC and released back to their communities in Syria, sometimes with tribes providing assurances that the returnees will not commit crimes, and sometimes without such sponsorships. This approach has produced mixed results, with some former fighters being successfully accepted into their communities of origin. However, families of the missing and those kidnapped by ISIS have complained about the lack of consultation before the SDC decided to release the fighters. Indeed, a blanket amnesty for individuals who committed international crimes runs counter to international law. In brief, de jure or de facto amnesties are not a complete solution to the overall problem of postwar detainees, particularly for foreign fighters or those responsible for more significant crimes.

Models of Justice

Since 2019, a number of ideas have been put forward to prosecute ISIS fighters. The Swedish government floated a proposal to create a tribunal or some other legal mechanism in the region to prosecute the fighters. Several NGOs criticized the idea as one-sided, arguing for a more holistic justice solution. At the time, the proposal did not garner significant support because it appeared designed to shirk states’ responsibility to repatriate their nationals. There were also concerns that short sentences would lead to ISIS fighters being quickly released.

The Guardian published an editorial calling for the creation of an ad hoc tribunal given the failure of the United Nations Security Council to refer the Syria situation to the International Criminal Court following a double veto by Russia and China. However, the ad hoc tribunals for Rwanda and the former Yugoslavia were also created by the UNSC, so this option would be similarly blocked by a Russian veto. Subsequent hybrid tribunals for Sierra Leone and Cambodia were created with the consent of the territorial state, which will not be forthcoming from Syria.

The obstacles to creating an international institution has turned the world’s attention to the domestic sphere. The French government has made a diplomatic push to have French ISIS fighters prosecuted in Iraq. Trials of ISIS fighters in Iraq are devoid of due process, however, lasting no more than 15 minutes and often resulting in the death penalty. This violates the international human right to due process. In addition, Iraqi courts are not sufficiently resourced to prosecute thousands of foreign fighters.

The most thorough analysis to date comes from Prof. André Nollkaemper’s legal opinion requested by the Dutch government in 2019, canvassing the legal justification for the creation of a treaty-based international tribunal with or without Syrian or Iraqi governmental support. He recommends that if an international tribunal is created, it should have “the broadest possible participation of states that can exercise jurisdiction over ISIS members as well as effective cooperation with Iraq or Syria.” (The document is only available in Dutch, but a good translation is available through Deepl.)

More recently, SDF trials have proceeded with some quasi-judicial proceedings, mainly against Syrian nationals. On March 18, the SDC reiterated its call for the creation of an international or hybrid tribunal to address the issue, for the provision of legal cooperation and international expertise. Two years from the first call for international assistance and with no solution yet on the table, a novel approach is required.

A Treaty-Based Terrorism Court

The most significant threat to security and stability are the 2,000 foreign fighters held by the SDF. This should be the first priority of the international community. For this unique problem, the international community should create a treaty-based terrorism court in collaboration with the Kurdistan Regional Government in Iraq (KRG) with arrangements to transfer convicted fighters to their home countries to serve their sentences.

There are at least 58 States with ISIS foreign fighters in SDF jails. Through a multilateral treaty, these States could pool their jurisdiction to form a tribunal to prosecute fighters for terrorism-related crimes. In this setting, jurisdiction may be granted for crimes committed abroad based on the active personality principle, whereby most domestic systems permit the prosecution of their own nationals for terrorism crimes. Crimes committed by these perpetrators – be it in Syria, Iraq, or elsewhere – would be within the jurisdiction of the court. The historical antecedent to this legal strategy is the London Agreement between the allied powers following WWII to prosecute Nazi leadership at Nuremberg. Due process rights would be guaranteed in the charter to the new tribunal, which would exclude the death penalty as inconsistent with international human rights standards.

The most appropriate locus for the tribunal would be in KRG-Iraq as it was also part of the territory controlled by ISIS. Victims and witnesses are located in the region and the area is relatively stable. Although trials would ideally be located where crimes occurred and where the detainees are now located, the SDC does not have legal personality to enter into international agreements. The Syrian government is not cooperating with efforts for international justice, and distrust between it and the SDF would not permit effective cooperation. There is political tension between the SDC and the KRG that would need to be resolved. But addressing this issue of mutual concern could be a basis for creating stronger relations, particularly if both entities are supported by the international community.

The subject-matter jurisdiction should be restricted to terrorism-related offenses for which the full-range of penalties remain available up to and including life-imprisonment. Prosecution might also include sexual and gender-based violence (see pp. 137-138). For example, Iraqi criminal law defines terrorism as “any criminal act” with terrorist intent. This could encompass SGBV, kidnapping and other crimes with specific intent. By limiting jurisdiction to these crimes, it would obviate the need to examine the contextual elements of crimes against humanity, war crimes, and genocide, which present resource-intensive and time-consuming issues. Of the foreign fighters, those most responsible for these international crimes, or those whose victims are foreign nationals, could still be prosecuted for atrocity crimes in their home jurisdictions. For example, the so-called ISIS Beatles are being prosecuted in U.S. courts (not without controversy). Indeed, it is important that the Yazidi genocide be recognized, and those most responsible for those crimes should be punished, either in regular Iraqi courts or pursuant to universal jurisdiction in other states.

A question arises as to the applicable substantive criminal law given that the foreign fighters are from over 50 different States. One view is that the substantive law of terrorism may be provided by Syrian law (Syrian counter-terrorism law 6/28/2012) because the crimes occurred in Syria. It may be argued, however, that this is not possible without the participation of the Syrian government. Further, this law has been abused by the Syrian government to prosecute political enemies, activists, and anyone suspected of opposing the regime.

Another view is that the national law that corresponds to the nationality of the accused must be applied, meaning a Kazakh ISIS fighter can only be convicted of crimes punishable under Kazakh law. This would complicate the work of the tribunal considerably. Nonetheless, the ministry of justice of each State could provide a legal memorandum to the tribunal setting forth the applicable substantive law for the terrorism offenses and a judicial office within the tribunal could compile these opinions and make them available to presiding judges (in Arabic). A third option would be to prosecute on the basis of Iraqi criminal law. Any crime with a connection to Iraq (e.g. where the perpetrator passed through Iraq for the purpose of joining ISIS and committing terrorism) could be prosecuted based upon Iraqi law now in effect. For crimes with no territorial connection to Iraq, it could extend its universal jurisdiction laws to encompass the crime of terrorism. The substantive law of terrorism under KRG-Iraqi laws (Law No. 13/2005; KRG Law No. 3/2006) could then be applied to all foreign fighters. This last option might be problematic as it would extend universal jurisdiction to less grave crimes such as membership in a terrorist organization. This approach may also trigger ex post facto concerns. A final, less optimal solution, would be to extend the jurisdiction of the treaty-based tribunal to grave breaches of the Geneva Conventions, crimes against humanity and genocide. These crimes have attained the status of customary international law and could satisfy the principle of legality. As noted above, this would require proof of all contextual elements

Criminal procedures may follow those established by the KRG (Criminal Procedure Code 23 of 1971 Kurdistan region of Iraq (as amended to 14 February 2010). This would obviate the need to draft and approve unique rules of procedure and evidence and would follow the example of the Khmer Rouge Tribunal, which adopted Cambodian law for its rules of procedure. (Note: The ECCC later chose to write its own rules based upon the already existing Cambodian rules of procedure). Although this arrangement is unconventional, it is not unprecedented. The Lockerbie criminal trial for the terrorist bombing of Pan Am Flight 103 took place in the Netherlands, but applied Scottish criminal procedure.

Some other practical concerns include the large caseload as well as funding. International tribunals are not accustomed to prosecuting a large number of accused persons. Indeed, they are designed to prosecute senior leaders and those most responsible for atrocity crimes. For example, the ICTY indicted 161 individuals. A more appropriate model might be prosecutions for piracy (a sister crime of terrorism). A decade ago, pirate attacks off the coast of Somalia skyrocketed. Hundreds of pirates were captured by international navies patrolling the area. In a program coordinated by the United Nations Office on Drugs and Crime and approved by the UNSC, specialized anti-piracy courts were designated in several States, including Kenya, the Seychelles, Mauritius, and Tanzania, which prosecuted over 1,200 pirates with the ultimate goal of transferring them to their home states. This strategy, along with international naval patrols and the use of private security contractors to defend commercial ships, was effective at suppressing piracy and trials were generally considered fair with convicted pirates returned to their homes to serve sentences. See here and here.

As for funding, Iraq is reluctant to bear the entire burden of these prosecutions. It has been reported that it has requested $1 million per prosecution of ISIS foreign fighters. However, a treaty-based terrorism court would not be an Iraqi institution. It would be supported by outside funding from international donors, which could control the budget and the functioning of the court. A final decision on the most appropriate personnel should be resolved following a decision on the applicable substantive law. It should be noted that courts using one official language (such as the Special Court for Sierra Leone) were much more efficient than courts with two or three languages such as the ICTR or ECCC. The official language of court should be Arabic and staffed with lawyers and judges who speak the language.

Rights of Survivors and the Search for the Missing

The brutality of ISIS continues to be felt by the survivors, especially those in Syria and Iraq whose family members were disappeared by ISIS and who remain missing. ISIS fighters are the single best source of information to obtain information on the missing, including the locations of ISIS prisons and mass graves. Tribunals prosecuting ISIS fighters should therefore provide opportunities to obtain this information during judicial processes. Prosecutors and judges should ask questions of ISIS fighters and survivors should be permitted to participate in these proceedings through a representative – as permitted by KRG criminal procedure. If the accused choose to remain silent during their substantive trials, they should be asked these questions again prior to sentencing.

Transfer of Prison Sentences – not extradition

Since 2019, despite repeated calls to repatriate foreign fighters, there has been very little movement by Western states. This is due in part to a fear that foreign fighters will be acquitted due to a lack of evidence, thus creating a security threat upon their release. A treaty-based court addresses this concern by prosecuting fighters prior to their repatriation. Ultimately, however, they should still be returned to their home countries through the transfer of sentences. The States signing the treaty could sign bilateral or multilateral transfer agreements with the KRG-Iraq to facilitate the return of foreign fighters to their home countries to serve their sentences consistent with human rights law.

In the event of acquittal, a separate system would need to be put in place for reintegration/ rehabilitation in their home countries.

Syrian and Iraqi ISIS fighters

A treaty-based terrorism court for foreign fighters would not be suitable to prosecute the remaining 8,000 ISIS fighters in SDF jails who are either Iraqi or Syrian. These individuals should be prosecuted in their home jurisdictions under pre-existing law and with the regular judicial processes in place.

Syria prosecutions should proceed against Syrian fighters in the SDC’s courts in northeast Syria pursuant to Syrian law. These courts will require international assistance to bring them into compliance with relevant human rights law. To this end, the international community should provide support in the form of infrastructure and expertise. As USAID contemplates reinitiating efforts to rebuild infrastructure in northeast Syria, it should consider a program to support the judiciary and criminal justice sector, including prison infrastructure and a program for rehabilitation and reintegration of ISIS fighters.

Iraqi members of ISIS should be extradited for trial in Iraq, which should also be financially supported by the international community. However, the international community should not become complicit in human rights abuses. The UNSG should seek diplomatic reassurances that the maximum penalty imposed will be life imprisonment, and that basic due process will be respected, including the right to a defense and a fair trial. International trial monitors should be present to ensure due process is respected.

Women and Children

The prosecution of foreign ISIS fighters in a treaty-based tribunal and the prosecution of Iraqi and Syrian ISIS fighters in their home countries will not remedy the situation of women and children remaining in camps in NE Syria. Some of these women are responsible for crimes and should be prosecuted. The treaty-based court could also be seized of these cases. Although there will need to be special provision to ensure the courts are equipped to address female detainees. This would add serious complications and prosecution of men detained in SDF jails might need to be prioritized.


The prosecution of ISIS fighters should not be confused with holistic justice for Syria. The Syrian government is the single largest perpetrator of atrocity crimes during the 10-year long conflict, and it must not be permitted to enjoy impunity. Justice is already proceeding in a piecemeal fashion through universal jurisdiction prosecutions in Germany, France, and elsewhere, and there is some hope that Syrian senior leaders will one day be held to account. But this should not prevent the international community from addressing the continuing national security and human rights emergency posed by the 10,000 ISIS fighters languishing in poorly resourced SDF prisons. To be sure, the challenges are significant but not insurmountable.

Image: Men, accused of being affiliated with the Islamic State (IS) group, sit on the floor in a prison in the northeastern Syrian city of Hasakeh on October 26, 2019. Photo by FADEL SENNA/AFP via Getty Images