Syrian fighter jets have bombed a Palestinian camp in Damascus, killing at least 25 people sheltering in a mosque in an area where Syrian rebels have been trying to advance into the capital.

The attack was part of a month-long campaign by President Bashar al Assad's forces to eject rebels fighting to overthrow him from positions hemming in Damascus.

It came a day after warplanes bombed rebels on the road to Damascus international airport.

Opposition activists said the deaths in Yarmouk, to which refugees have fled from other fighting in nearby suburbs, resulted from a rocket fired by a warplane hitting the mosque.

A video posted on YouTube showed bodies scattered on the stairs of what appeared to be the building.

The latest battlefield accounts could not be independently verified due to tight restrictions on media access to Syria.

It was the first reported aerial attack on Yarmouk, on the southern fringes of Damascus, since a popular uprising against Mr Assad erupted 21 months ago and grew from peaceful street protests into an armed insurgency.

Syria is home to more that 500,000 Palestinian refugees, most living in Yarmouk, and both Mr Assad's government and the mainly Sunni Muslim Syrian rebels have enlisted and armed Palestinians as the uprising has mushroomed into a civil war.

Heavy fighting broke out 12 days ago between Palestinians loyal to Mr Assad and Syrian rebels, together with a brigade of Palestinian fighters known as Liwaa al Asifah (Storm Brigade).

Clashes flared anew after yesterday's air strike between Palestinians from the pro-Assad Popular Front for the Liberation of Palestine-General Command (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, it said.

Opposition activists and the Observatory said many families were trying to escape the internal Yarmouk clashes.

The army's infantry college in northern Aleppo was captured on Saturday after five days of fighting, a rebel commander with the powerful Islamist Tawheed Brigade said. He added that the rebels had surrounded the college, located 10 miles (16 km) north of Aleppo, Syria's largest city, three weeks ago.

"At least 100 soldiers have been taken prisoner and 150 decided to join us. The soldiers were all hungry because of the siege," said the commander.

Some 40,000 Syrians have now been killed in what has become the most protracted and devastating of the Arab popular uprisings that have toppled several dictators since early 2011.

Damascus has accused Western powers of backing what it says is a Sunni Islamist "terrorist" campaign to topple Mr Assad, a member of the minority Alawite sect affiliated with Shi'ite Islam.