At least half the residents of Syria’s largest Palestinian refugee camp have fled their homes following a day of heavy bombardment by government forces, as Palestinian militiamen backed by the Syrian army clashed with opposition forces on Monday.

Palestinian media reported a death toll of between 20 and 49 residents at Yarmouk refugee camp south of Damascus, which houses some 150,000 Palestinian refugees. Syria is home to nearly 500,000 registered Palestinian refugees, many of whom have fled to neighboring Jordan and Lebanon since the civil war intensified in late 2011.

The Syrian army has over the past months repeatedly entered Yarmouk camp to repel Free Syrian Army fighters who captured sections of the camp and nearby neighborhoods. But for the first time on Sunday, a MiG fighter jet fired two missiles into the camp, killing and injuring dozens.

Anwar Abdul Hadi, the PLO’s political representative in Syria, told Ma’an news agency on Monday that approximately half the residents of the camp had fled to nearby mosques, schools and UN compounds in search of safety.

Abdul Hadi blamed the violence on members of the opposition Free Syrian Army, whom he said entered the camp in large numbers and began clashing with local militants.

According to the Syrian government daily Al-Watan, however, members of the Popular Front for the Liberation of Palestine-General Command based in the camp exchanged mortar fire with “armed gangs” — a term used by the government to describe the FSA —  forcing the Syrian army to intervene and bomb opposition posts from the air.

‘The myth of Palestinian neutrality crumbled early on in the war. The more the conflict intensifies the more pressure there is on Palestinians to take sides’

Al-Watan published a communique by the PFLP-GC, which is loyal to the Assad regime, claiming that the FSA entered the camp in order to “harm the right of return by expelling Palestinians from Syria.”

Benedetta Berti, a research fellow at Tel Aviv University’s Institute for National Security Studies specializing in Lebanon and Syria, said that Palestinians in Syria were forced to end their previous neutrality toward the regime as fighting in the country intensified.

“The myth of Palestinian neutrality crumbled early on in the war,” Berti told The Times of Israel. “The more the conflict intensifies the more pressure there is on Palestinians to take sides.”

Berti noted that Palestinian groups such as PFLP-GC who support Assad are the exception rather than the rule.

On Sunday, officials in Fatah and Hamas were engaged in intense international efforts to end the onslaught on Yarmouk camp. PA President Mahmoud Abbas called UN Secretary General Ban Ki Moon and Arab League Secretary General Nabil Al-Arabi, asking them to intercede on behalf of the camp.

Abdul Hadi, the PLO representative in Syria, said that Abbas was also in contact with the Syrian regime and with UN representative to Syria Lakhdar Brahimi. He said the regime has committed not to approach the camp again.

Osama Hamdan, Hamas’s representative for international affairs, told Al-Aqsa news channel Sunday that his movement was in touch with “various elements” to stop the bloodshed in the refugee camp.

A former ally of Bashar Assad, Hamas shut its Damascus offices in January and left Syria in protest against Bashar Assad’s bloody repression of the Syrian uprising.

But Yarmouk was not the only Palestinian refugee camp in Syria targeted on Sunday. Palestinian daily Al-Quds reported the death of three children in Sayida Zainab refugee camp as a result of a mortar shell that struck the camp.

Four men were killed by a bomb blast in Yarmouk camp on November 23. The bomb was planted under the car of a member of PFLP-GC, who was seriously wounded in the incident.