Beirut: US-backed fighters have seized a key ISIS stronghold in northern Syria after two months of heavy fighting and freed hundreds of civilians the extremists had used as human shields, Syrian Kurdish officials and an opposition activist group said on Saturday. Nasser Haj Mansour, of the predominantly Kurdish Syria Democratic Forces said that the town of Manbij “is under full control,” adding that operations are ongoing to search for any ISIS militants who might have stayed behind.