Syrian rights activists say a military crackdown on opposition protesters in the central part of the country has killed at least 15 civilians since Sunday and injured dozens more. The demonstrators were killed as government forces backed by tanks, artillery and helicopters continued to attack the cities of Talbiseh, Rastan and other central communities where residents have staged anti-government protests in recent days. Rights groups said three civilians were killed yesterday in Talbiseh. Residents also found the bodies of two people thought to have been killed by Syrian troops in Homs, Syria's third-largest city. In a significant new development, the residents of Talbiseh and Rastan used automatic rifles and rocket-propelled grenades to repel advancing troops. U.N. High Commissioner for Human Rights Navi Pillay said the repression of opposition movements in Syria and Libya is shocking for its brutality and magnitude.