BEIRUT — The U.S. government has suspended deliveries of aid to Syrian rebels after an Islamist group overran the main warehouses where the supplies were stored, the U.S. State Department said Wednesday. The cluster of warehouses in the northern Syrian town of Atmeh served as the chief conduit for supplies into Syria for the Supreme Military Council, the Western-backed body that oversees moderate rebel factions fighting in Syria. At the time of the takeover, the warehouses contained U.S.-supplied food, medical kits, some communications equipment and several pick-up trucks, typical of the items the United States is sending under a $16.9...