BEIRUT (Reuters) -- Syrian fighter jets rocketed the Palestinian Yarmouk camp in Damascus on Sunday, killing at least 25 people sheltering in a mosque in an area where Syrian rebels have been trying to advance on the capital, opposition activists said.
They said the deaths resulted from a rocket hitting a mosque in the camp, to which refugees have fled from other fighting in nearby suburbs of Damascus. It was the first reported aerial attack on the camp since the revolt against President Bashar Assad erupted last year.
Yarmouk, in southern Damascus, is part of an arc sweeping from the east to southwest of the Syrian capital where Assad's forces have been trying for several weeks to push back rebels from the gates of his power base.
A video posted on Youtube shows bodies and body parts scattered on the stairs of what appears to be the mosque.
Syria is the home of more that 500,000 Palestinian refugees, most of them living in Yarmouk. Assad's government and Syrian rebels have enlisted and armed Palestinians refugees during the 21-month uprising, which has escalated into a civil war.
Heavy fighting broke out 12 days ago between Palestinians loyal to Assad and Syrian rebels, together with a brigade of Palestinian fighters known as Liwaa al-Asifah (Storm Brigade).
The fighting intensified on Saturday with rebels gaining ground inside the camp, forcing Ahmed Jibril, a veteran leader of a Damascus-based Palestinian faction that back Assad to leave the capital with his son.
Jibril's PFLP-GC has maintained strong ties to Assad throughout the uprising, unlike Hamas whose Damascus-based officials - including leader-in-exile Khaled Mashaal - quietly pulled out of Syria as the mainly Sunni Muslim revolt against Assad gained momentum.
Clashes flared anew after Sunday's air strike between Palestinians from the PFLP-GC, and Syrian rebels together with other Palestinian fighters, according to the Syrian Observatory for Human Rights monitoring group.
Some PFLP-GC fighters were killed, the London-based Observatory said.
Opposition activists and the Observatory said many families were trying to escape the internal Yarmouk clashes.