Fighters from the Syrian Democratic Forces and other U.S.-backed troops have been preparing to take control of Raqqa for months. AP hide caption toggle caption AP The Two-Way U.S.-Backed Fighters Begin Offensive To Push ISIS From Its 'Capital' June 6, 2017 Raqqa is the most important stronghold for the militant group in Syria and fell under its control in 2014. This offensive is expected to be difficult and is seen as pivotal in the fight against ISIS.