BEIRUT ( AP) — Syrian troops clashed with army defectors and shelled rebellious districts in the central city of Homs today, killing at least 11 civilians a day after the government claimed it had begun a troop withdrawal ahead of the deadline to implement an international truce plan.

Activists said the latest deaths included a man and his son who died in gunfire during fighting in the Qusour district of Homs. They said the renewed violence proved President Bashar Assad’s regime was not serious about implementing the cease-fire brokered by former U.N. chief Kofi Annan.

Russia, a key ally of Assad, warned other nations not to arm the Syrian opposition, saying it would only escalate hostilities. Saudi Arabia and Qatar, two Sunni- ruled nations, have backed the idea of arming the rebels fighting government forces, but the West remains opposed. Western nations, however, did create a multimillion-dollar fund for the opposition at a meeting in Istanbul.