A contingent of several hundred Marines has arrived in Syria to provide artillery support to U.S.-backed Syrian rebels preparing to retake Raqqa, ISIS's de facto capital in Syria, according to a U.S. military official.
The number of Marines associated with the battery and support elements number "more than several hundred," said the official. The U.S. military is authorized to have up to 503 American troops inside Syria to advise and assist the local Syrian Democratic Forces (SDF) fighting ISIS.