Talks were held on Wednesday aimed at removing both rebel and pro-government fighters from a Damascus Palestinian refugee camp after deadly clashes, a Palestinian relief official told AFP, as the UN spoke of residents fleeing in droves.
"Palestinian organisations that have remained neutral are overseeing talks between the (rebel) Free Syrian Army and Syrian troops, to keep the camp out of the conflict," the official said on condition of anonymity.
"So far, the talks have been unsuccessful."
A plan to put the Yarmuk refugee camp in the south of the Syrian capital under the control of "neutral" Palestinian officials is under discussion.
In Geneva the United Nations Relief and Works Agency for Palestinian refugees said that as many as 100,000 Palestinians may have fled Yarmuk over the past few days because of fighting there.
"People are still leaving in droves," UNRWA deputy chief of staff Lisa Gilliam told AFP, adding that the organisation estimated that around two thirds of the some 150,000 residents of Yarmuk camp appeared to have left.
Fresh fighting on Wednesday on Yarmuk's outskirts killed a civilian and four members of the pro-regime Palestinian Front for the Liberation of Palestine-General Command, the Syrian Observatory for Human Rights said.
The pro-regime Syrian daily Al-Watan said the army "deployed additional reinforcements to the edges of Yarmuk camp" ahead of storming it.
Palestinians have been divided over the 21-month uprising against the rule of Syrian President Bashar al-Assad, who is from the Alawite offshoot of Shiite Islam but whose regime has long given shelter to hardline militant factions.
According to UNRWA, there are 486,000 Palestine refugees living in nine official and three unofficial camps across Syria.
Those fleeing Yarmuk were seeking shelter in other parts of Damascus or elsewhere in Syria, and a growing number was crossing the border into Lebanon, Gilliam said.
Lebanese authorities have said that some 2,200 Palestinians have crossed the border since Saturday.
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Gilliam urged all sides to respect the neutrality of the Palestinians in the Syrian civil war and called on neighbouring states to allow fleeing Palestinians to enter.
The Palestinians, she said, "are historically a population that is targeted and scapegoated... They are an easy target."
An AFP photographer reporting from the Syria-Lebanon border on Wednesday said hundreds of Palestinians were seeking to cross, mostly women, children and the elderly.
"We don't know where to go or what we are going to do," said Umm Ahmed, who waited at the Masnaa crossing with her five children and her husband, who she said was wounded when a building collapsed after an air strike.
She said her husband was trapped under the rubble for a whole day and by the time rescue came his leg was gangrenous.
Until last weekend, Yarmuk had provided refuge for hundreds of Syrian families forced to flee their strife-torn towns and cities.
But on Sunday, warplanes launched the first air strike on Yarmuk since the start of Syria's conflict, killing at least eight civilians. Violence has since raged in the camp.
Backed by anti-regime Palestinian fighters, rebels have expelled most pro-Assad fighters from Yarmuk, the Syrian Observatory said.
"The camp is now nearly empty of its residents," an activist who identified himself as Rasim told AFP via the Internet.
"It's a real humanitarian catastrophe," said another resident.
Also on Wednesday, Palestinian president Mahmud Abbas urged the international community to help Palestinian refugees fleeing the fighting to enter the West Bank or Gaza.