The Palestinian Authority leadership condemned the Syrian regime on Sunday after Bashar Assad's forces attacked a Palestinian refugee camp in Damascus, killing at least 25 people.

"We hold Bashar Assad and his regime responsible for this crime in Yarmouk camp, which clearly reveals that this regime knows no limits in its approach to criminal murder and destruction," Senior PLO official Yasser Abed Rabbo told Reuters.

"In the Yarmouk refugee camp massacre and everywhere in Syria, the international community must put an end to a system of murder and terrorism in Syria before they burn the whole region."

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.

A video posted on Youtube shows bodies and body parts scattered on the stairs of what appears to be the mosque.

President Abbas told official news agency Wafa that he was very concerned that Palestinians in Syria were begin affected by Syria's internal conflict and called for an end to violence against refugee camps in the country.

He urged the international community to intervene to protect Palestinian refugees in Syria.

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 Palestinian 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.

In November, the PLO said that around 600 Palestinians had been killed in the Syrian conflict.