U.S.-backed Syrian forces are conducting search operations in tunnels a day after seizing an encampment where Islamic State militants had been making their last stand in Syria.

Ciyager Amed, an official with the Kurdish-led Syrian Democratic Forces, says they are searching for any IS militants still hiding in tunnels in a riverside pocket in the village of Baghouz.

Associated Press journalists saw SDF soldiers loading women and children into trailer trucks on the hilltop over Baghouz, in a sign evacuations were ongoing Wednesday. Black smoke could be seen rising from a part of the village.

U.S.-backed Syrian forces on Tuesday seized control of the encampment held by IS after hundreds of militants surrendered overnight, signaling the group’s collapse after months of stiff resistance.