The US’ key anti-ISIS partners in Syria said on Wednesday that the ISIS detention facilities they guard are coming under attack and that they have been forced to halt anti-ISIS operations, complicating the US military’s efforts to prevent the terror group from reconstituting following the ouster of Syrian President Bashar al-Assad.

Bashar Assad instead became a doctor in the 1980s and was studying in London to be an ophthalmologist in the early 1990s. But when Basil Assad died in a car accident in 1994, Bashar Assad was recalled to Syria to replace his brother as heir apparent.

Gen. Mazlum Kobani, commander of Kurdish forces in Syria, said recent decisions by the U.S. in Syria potentially “leaves a vacuum behind that can be taken advantage of by ISIS.”

The top commander of the US-backed and Kurdish-led Syrian Democratic Forces warns a resurgent ISIS is starting to take advantage of the fall of former Syria President Bashar al-Assad.