U.S.-backed Syrian fighters said Saturday they have concluded a 24-day sweep at a sprawling camp in northeast Syria housing tens of thousands of women and children linked to the Islamic State group. Dozens of extremists were detained and weapons were confiscated in the operation at al-Hol camp, which began on Aug. 25, the U.S.-backed forces said. The U.S.-backed force said two of its fighters were killed in clashes with extremists inside the camp during the operation. IS sleeper cells preparing a new generation of militants — boys and girls being fed extremist ideology to eventually try and se…