" Activists said the blast occurred after rebels had fired rockets at southern neighborhoods that are heavily populated with Alawites, the religious sect to which Mr. Assad belongs. Alawites play a leading role in his security forces. A Homs activist reached via Skype who gave his name as Abu Bilal said that civilians lived in the area before the war but that it had since become like a base for Mr. Assad’s forces to launch attacks on the rebels. He said the blast was like “a volcano.”"