A mosque in the Palestinian neighborhood of Yarmouk in southern Damascus that was sheltering some 600 refugees from neighboring districts was been attacked from the air and hit by at least one rocket, and there are reports of many casualties, according to the BBC.

According to Euronews, at least 25 people were killed in the strike.

The neighborhood is home to over 100,000 Palestinians, many of whom are supporting Bashar al-Assad. But it is also the scene of fighting between pro and anti-Assad Palestinian forces, the latter fighting alongside the rebels.

Yarmouk is a stronghold of the pro-Assad Popular Front for the Liberation of Palestine (PFLP), which has been fighting against the rebel forces, while other Palestinians are fighting alongside the rebel forces.

It was reported Saturday that PFLP military commander Ahmed Jibril had fled the camp with his son for Tartous, a stronghold of Bashar al-Assad’s Alawite minority.

Palestinian Authority head Mahmoud Abbas called on Sunday for an “immediate halt” to the shelling of the Palestinian camps in Damascus.

“We call on the warring sides in Syria to spare the Palestinian people and their camps in Syria,” he said in a statement carried by official Palestinian news agency WAFA, adding that bombing of the refugee camps “must be stopped immediately.”

 “We also call on the international community to take immediate action to provide protection to our people in Syria,” Abbas said, adding that the Palestinians were “not involved” in the conflict.