“This place is a literal breeding ground for the next generation of Isis,” Gen. Michael “Erik” Kurilla, commander of U.S. Central Command, said in a statement after recently visiting al-Hol. “ISIS seeks to exploit these horrific conditions.”

The growing terrorism threat poses a political problem for Biden, threatening to undermine his vow not to allow ISIS to reconstitute. Biden has insisted the U.S. can continue to effectively fight terrorism despite an increasingly shrinking troop presence overseas, pointing to two operations this year: a raid by U.S. special forces in northwestern Syria that led to the death of ISIS’s top leader and a drone strike in Afghanistan that killed the head of al-Qaeda. 

The situation at al-Hol threatens to undermine all of that.

“It’s a complex problem. There are humanitarian elements to it, but there’s a security element as well,” a senior administration official said. “We are trying to look for creative approaches and new energy and resources to get at this same problem that has been evolving over the last few years.”

In the past three years, al-Hol has grown from 10,000 to roughly 57,000 residents, about 90% of them are women and children , according to the U.S. government. About 40,000 of the children are under the age of 12, the government data says, and at least 80 babies are born there each month. And about 8,000 of the women are “jihadists and wives and widows of ISIS fighters” who have organized their own “religious police units,” the Carnegie Endowment for International Peace recently reported.

A recent, nearly three-week operation at al-Hol — conducted by the Syrian Democratic Forces, with the U.S. military providing intelligence and surveillance — found women and girls who were chained, tortured and sexually abused, according to the U.S. military. One Yazidi girl found inside a tent had been held captive by ISIS for eight years, routinely raped and sold as a slave since she was taken from her family in Iraq when she was 9. 

The operation led by the SDF, which is nominally in charge of the camp, resulted in the arrest of hundreds of ISIS fighters and the discovery of dozens of tunnels where the group’s operatives had stored weapons and supplies, including more than 50 pounds of explosives. 

Administration officials are particularly worried that the tens of thousands of children at al-Hol are especially vulnerable to being recruited by ISIS, or forced to join. 

“We’re really concerned that al-Hol is deeply tied to one of our primary objectives for all of Syria, which is to prevent the resurgence of ISIS,” the senior administration official said.

U.S. officials have said there is no military solution to al-Hol, and instead are trying to stop the growth of ISIS through diplomatic outreach. Officials at the State Department, National Security Council and Pentagon are working on the plan, which also includes improving living conditions for those who cannot leave. 

The U.S. is adding the issue to diplomatic and military engagements, the five administration officials said, including asking every country with citizens at al-Hol what the hurdles are to repatriating them.

“The United States supports and applauds recent repatriations,” a spokesperson for the NSC said in a statement. “Our effort to encourage repatriations and offer support is ongoing.”

The NSC spokesperson deferred to the countries that have agreed to repatriate their citizens for comment on their efforts.

The camp’s size and makeup dramatically changed in March 2019 when the Syrian Democratic Forces defeated ISIS fighters at Baghouz, Syria. The battle there was seen as ISIS’ last stand, and its defeat marked the fall of the terrorist group’s self-proclaimed caliphate.