A Palestinian minister on Tuesday accused "terrorists" fighting to topple Syrian President Bashar al-Assad of blocking aid access to the Yarmuk refugee camp in southern Damascus.
Rebels control swathes of Yarmuk, but for months government forces have imposed a suffocating siege on the camp, where some 20,000 Palestinians live despite terrible shortages.
Palestinian labour minister Ahmad Majdalani, who was visiting Damascus to negotiate aid access to the camp, said its Palestinian residents must not be used as "hostages" in the conflict.
An aid convoy heading to Yarmuk was targeted on Monday "some 100 metres (yards) away from the agreed meeting point," on the edges of the camp, Majdalani said at a press conference in Damascus.
He said "the source of fire was known... to be controlled by Al-Nusra Front, Ahrar al-Sham and Suqur al-Golan," directly accusing rebel groups battling Assad's troops.
Majdalani added "all these groups are known for their terrorist links and methodology."
The minister also said Palestinians "everywhere know... that those who have taken the camp hostage are these groups, not the Syrian authorities."
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Some 45 people have died in recent months because of food and medical shortages in Yarmuk, the Syrian Observatory for Human Rights monitoring group has said, with the most recent death on Tuesday.
Monday's aid convoy was the sixth to have failed to enter the camp.
Palestinian sources have told AFP the convoys were blocked from entering by gunfire, but did not specify who was responsible.
But the opposition Yarmuk local coordination committee said Assad loyalists had blocked the convoy.
"The Syrian regime and the (pro-Damascus) Popular Front for the Liberation of Palestine-General Command... kickstarted a clash targeting the Palestinians and everyone else there, to continue with their brazen policy of starvation," the activist group said via Facebook.
The convoy of six trucks carried 1,700 30-kilogram food parcels, each of which could feed a family for 20 days.
In a reflection of the desperation in the camp, footage distributed by activists on Tuesday showed a young man from Yarmuk crying for assistance.
"We don't have the money to pay for a kilo of rice, we don't have money to pay for a kilo of bulgur... We don't have anything to do with this conflict. We just want to eat and drink, we want to be safe," he wept.