PENTAGON - Efforts to secure prisons holding thousands of captured Islamic State fighters appear to be on the verge of crumbling, a development that could help strengthen the terror group's efforts to re-emerge in Syria and Iraq.
For months, officials have said the prisons, run by the U.S.-backed Syrian Democratic Forces, were "good enough" to hold the fighters, many of whom were captured following the fall of Baghuz, the terror group's last Syrian stronghold, in March.
But as efforts to repatriate IS foreign fighters to their countries of origin have stalled, and as thousands more wait to face some sort of justice, fears are growing that the prisons may be reaching a breaking point.
"There are not prisons controlled by forces in northeast Syria that can house 10,000 ISIS fighters," Chris Maier, director of the Pentagon's Defeat IS Task Force, told reporters Wednesday, using another acronym for the terror group.
"This is not sustainable over time," he added, noting that the United States' anti-IS coalition partners "share that assessment."
Many of the prisons are buildings, like schools, that were quickly converted into detention facilities as the U.S. and coalition forces rolled back the last of the terror group's territory in Syria.
Soon, the prisons were close to overflowing. In March, the U.S. began sending the SDF material for repairs and refurbishment.
Yet those repairs have gone only so far, as the number of IS prisoners in SDF custody has remained steady, including an estimated 2,000 or more foreign fighters from over 60 countries.
"We ask for their countries to get them back. Nobody responds," Sinam Mohammed, the U.S. representative of the Syrian Democratic Council (SDC), said last week during a forum in Washington.
"We ask now for having international tribunals for these fighters," she added. "We don't have any support."
In the meantime, the danger has been growing.
"We've seen a number of attempted jailbreaks," Nathan Sales, the State Department's counterterrorism coordinator, told reporters in August. "The risk that they could get out is not trivial."
Counterterror experts also fear that once the IS prisoners do get out, they will be more capable and more lethal than before.
"We're kind of heading, I think, in this slow-motion disaster," Shiraz Maher, director of the International Center for the Study of Radicalization and Political Violence, told an extremism conference at the U.S. Institute of Peace on Wednesday.
"What's particularly striking now is we are essentially repeating many of the errors that were made in Iraq after 2003, where we gathered lots of really serious guys from al-Qaida, put them together in Camp Bucca, and then did nothing about it. And later, we released these individuals, who returned more or less immediately to their activities and went on to create ISIS," he said. "There is no off-ramp."
For now, the U.S. is providing the SDF with some help, but nothing that will extend the life of the makeshift prisons themselves.
"We continue to provide basic training and assistance to the forces that are serving that kind of warden- or prison guard-type role," Maier said.
"We're more focused on getting them [the prisons] shut down and people moved to more secure facilities, as opposed to improving them," he said.