The US's Syrian partners are still guarding hundreds of ISIS prisoners

• In January, hundreds of ISIS prisoners attempted to break out of a prison in Syria.
• US-backed Kurdish forces responded, quelling the jailbreak after 10 days of fighting.

While the world's attention is fixed on Ukraine, the US and its Kurdish partners are sitting on a powder keg in Syria.

Thousands of ISIS fighters are being held in prison camps in northern Syria. Although the Kurdish-led Syrian Democratic Forces, with the support of the US and the anti-ISIS coalition, are guarding them, these detainees are still a challenge to regional security and stability.

That became apparent when thousands of them tried to break out in January, triggering a days-long battle.

Prison break

On January 20, hundreds of ISIS detainees held at the Ghweran prison in the city of Hasakah in northeastern Syria revolted and tried to take over the Kurdish-controlled camp, which was crowded with more than 3,000 militants and juveniles.

The revolt began when a car bomb detonated at the prison gate and ISIS fighters rushed the facility. Detainees started burning tires and other materials to create chaos and disrupt the Kurdish forces guarding the prison.

According to ISIS, the goal was to liberate the entire prison and for the detainees to rejoin the terrorist group.

The SDF, supported by US special operators and airstrikes, counterattacked and quelled the revolt, killing several ISIS fighters. At least seven Kurdish fighters were killed during the 10-day operation.

"Thanks to the bravery and determination of the SDF, many of whom paid the ultimate sacrifice, ISIS failed in its efforts to conduct a large-scale prison break to reconstitute its ranks," US national security advisor Jake Sullivan said.

The prison revolt may have stemmed from the conditions in which the ISIS prisoners are being held and their treatment.

Sullivan highlighted the need for cooperation between countries in the region and countries from which ISIS' foreign fighters have come to deal with the as many as 12,000 ISIS fighters who are being held in northern Syria.

In a statement after the prison break, the US State Department called on partners in the anti-ISIS coalition "to improve the secure and humane detention of ISIS fighters, support rehabilitation initiatives, and urgently repatriate their nationals and other detainees remaining in northeast Syria."

The US "will continue its stabilization and other programs in the region to support these efforts," the department said in the statement.

Western countries, including the UK, France, and Germany, that have citizens who joined ISIS were caught off-guard. This is a legally unexplored territory, and countries weren't sure how to treat those detainees and, in some cases, have tried to shed any responsibility for them, stripping those foreign fighters of citizenship.

YPG and US special operations

The Kurdish forces that responded to the prison break didn't do so alone. The US Army's elite Delta Force, traveling in their distinctive Armored Ground Mobility Systems, were on the ground and supported the Kurdish operation to quell the revolt.

Delta Force has built a strong partnership with the YPG, the SDF's main force, dating back to 2014-2015, when ISIS was its strongest.

Master Sgt. Joshua Wheeler, a distinguished Delta operator, was killed during an October 2015 operation to rescue dozens of YPG fighters who had been captured by ISIS. Sgt. Maj. Thomas Payne, another Delta Force member, received the Medal of Honor for his actions during the same mission.

"The Kurds are legit good fighters and they are very easy to work with. They get us and we don't have to cross too many cultural barriers to reach them," a Green Beret assigned to a National Guard unit said. "I think history will remember the Kurds as one of the top partner forces the [US Army Special Forces] Regiment has worked with."

The US has a long relationship with the Kurds, though Washington has been criticized for relying on them and then leaving them vulnerable to attack.

US special-operations units have worked with the Kurds since the Gulf War and during and after the 2003 invasion of Iraq, the Green Beret, who was not authorized to speak to the media, told Insider.

"They are disciplined and good fighters. They can learn fast and take the initiative once trained," the Green Beret said.

In July, the Pentagon stood up Special Operations Joint Task Force-Levant to replace Special Operations Joint Task Force-Operation Inherent Resolve. SOJTF-Levant is a joint special-operations force composed of units from across US service branches. It falls under Special Operations Command Central, the special-operations component of US Central Command, which oversees US military operations in the region.

The new task force was meant to better reflect the operational environment that US special operators now face. It works closely with the Kurdish-led SDF.

"Throughout the years, we've trained the [Peshmerga] in small-unit tactics, direct action, sensitive site exploitation, and special reconnaissance, to name a few," the Green Beret said, using a name for Kurdish forces in Iraq. "They've got to a point where they know what they are doing and we are just supporting them on the ground or from the air."

Stavros Atlamazoglou is a defense journalist specializing in special operations, a Hellenic Army veteran (national service with the 575th Marine Battalion and Army HQ), and a Johns Hopkins University graduate.