Fighting in the Damascus district of Yarmouk have interrupted aid distribution to thousands of besieged Palestinian refugees, the United Nations said on Monday.
The clashes broke out on Sunday in Yarmouk, where 20,000 people have been trapped for months by Syria's civil war and are dependent on humanitarian supplies delivered by UNRWA, the UN agency which supports Palestinian refugees.
A Palestinian group that supports President Bashar al-Assad, the Popular Front for the Liberation of Palestine-General Command (PFLP-GC), blamed the fighting on al-Qaeda-linked al-Nusra Front.
"Terrorist groups from the Nusra Front and their takfiri brothers... infiltrated Yarmouk Camp," Hussam Arafat, a PFLP leader said in a statement on Sunday.
He added that the jihadist fighters have occupied a square in the center of the camp and that their presence threatens humanitarian efforts.
Al-Nusra confirmed that it has entered the camp. The fighting broke a fragile truce that has been in place since February 11 when non-Palestinian fighters agreed to leave the camp to allow aid workers to delivers crucial supplies.
UNRWA spokesman Chris Gunness said the UN agency was unable to distribute food parcels in Yarmouk on Sunday and called on all sides in the conflict to immediately allow the resumption of the aid operation.
"UNRWA remains deeply concerned about the desperate humanitarian situation in Yarmouk and the fact that increasing tensions and resort to armed force have disrupted its efforts to alleviate the desperate plight of civilians," he said.
Yarmouk is one of several besieged districts in Damascus and other cities. Most areas have been cut off by government forces who are trying to box in the rebels.
But insurgents are also surrounding pro-government towns in the northern province of Aleppo.
Local ceasefires in Yarmouk and other Damascus suburbs, as well as the central city of Homs, have allowed some civilians to escape and limited amounts of food to be taken in, but the deals are fragile and in some cases the sieges have resumed.
The United Nations Security Council called last month for the immediate lifting of all the sieges and demanded all sides allow access for humanitarian aid.
(Reuters, Al-Akhbar)