The United States military has in its custody an American person who surrendered to Syrian Democratic Forces after fighting for ISIS in Syria, NBC News reported.
U.S. officials have previously said that roughly 250 people left the U.S. to join ISIS. It's not clear how many remain.
The American who surrendered Tuesday hasn't been publicly identified. He was taken into custody during a battle in the Deir-al-Zour region, which the Daily Beast first reported.
"The U.S. citizen is being legally detained by Department of Defense personnel as a known enemy combatant," Pentagon spokesman Maj. Adrian J.T. Rankine-Galloway said.