Most of the Syrian opposition fighters in the Palestinian refugee camp of Yarmuk in southern Damascus have withdrawn, a Palestinian official told AFP on Sunday.
Anwar Abdel Hadi, an official with the Palestine Liberation Organisation, said the pullout came after an agreement between the rebels and Palestinian factions in Yarmuk.
The Syrian Observatory for Human Rights said the accord may help ease a crippling army siege imposed more than 200 days ago that has trapped thousands of civilians and sparked famine.
"Most of the gunmen have pulled out of the camp," Abdel Hadi said.
"Palestinian fighters have deployed to the outskirts of the camp to prevent the entry of any non-Palestinian gunmen," he added.
Observatory chief Rami Abdel Rahman said the departure of fighters could pave the way to an easing of the siege on Yarmuk, where more than 100 people have died of malnutrition and lack of medical aid.
"The situation has become unbearable," Abdel Rahman told AFP.
"People are hungry and the situation has worsened over the past four months, that is why this agreement was reached," he added.
Last month, Palestinian factions negotiated a deal under which the UN agency for Palestinian refugees, UNRWA, was able to begin distributing food to Yarmuk residents.
Under the operation, 1,500 civilians were also evacuated.
The aid distribution, however, was halted on February 8 following renewed fighting in the camp between opponents and supporters of the Syrian regime.
Abdel Hadi said aid could re-enter the camp once all the fighters leave.
A Palestinian delegation is due to tour the camp on Sunday "to ensure it is free of gunmen" and within 24 hours bomb disposal experts will go in to defuse explosives and mines.
"Humanitarian aid can resume immediately after these processes are completed and state institutions return to the camp," he said.
The camp was once home to some 150,000 Palestinians, as well as Syrian residents.
But large parts of it have been destroyed by fighting and many residents have fled, with just 18,000 left behind and under a tight army siege imposed after rebels took control of the camp.
On Saturday, UNRWA urged renewed access to Yarmuk, warning the supplies it had delivered would now be running out.
"We have not distributed food there over a week now which is potentially life-threatening for the besieged civilians trapped by the conflict," UNRWA spokesman Chris Gunness said.