The UN's World Food Programme warned Tuesday that the spiralling violence in Syria was making it increasingly difficult to distribute food in the war-torn country.
"Food needs are growing in Syria," said WFP spokeswoman Elisabeth Byrs, whose organisation distributes most of its aid in Syria through the Syrian Arab Red Crescent (SARC).
Citing SARC figures, Byrs told reporters in Geneva that nearly 2.5 million people currently need emergency food assistance, up from the 1.5 million estimated two months ago.
Yet WFP is only able to reach 1.3 million people each month, she said, lamenting the "escalating violence", especially in the north of the country.
WFP said in a statement it had seen a sharp rise in the number of attacks on its aid trucks in recent weeks.
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Since the beginning of October, the organisation said, armed groups have stolen or confiscated around 10 of its trucks.
"In many of these incidents, WFP was able to recover the food after negotiations through third parties, but truck drivers have become more reluctant to drive on some roads or deliver food assistance to risky areas," it explained.
Fuel shortages have also impacted WFP's ability to distribute aid, it said, adding that there were not enough humanitarian partners on the ground to help deliver the aid.
The WFP appeal came after UN aid chief Valerie Amos at the weekend asked the Syrian government to allow 10 additional aid organisations into the country to help the increasingly desperate population.
People on the ground are going hungry, Byrs added, saying there was a "bread crisis" because fuel shortages had forced bakeries to close.
The UN, which is set to issue an appeal for funds to finance all of its aid work in Syria in 2013, estimates that around four million Syrians are in need of humanitarian aid.
WFP meanwhile said it aimed to help 1.5 million people by the end of this month, but stressed that if it was going to continue providing food to so many people it would need another $132 million (100 million euros).