GENEVA: Hundreds of wounded need evacuation from besieged eastern Aleppo, where medical supplies are running low and there are only rations for a quarter of the population, the United Nations deputy Syria envoy Ramzy Ezzeldine Ramzy said on Thursday.

Ramzy, speaking to reporters in Geneva after the weekly meeting of the humanitarian task force, called for Russia and the United States to "resurrect" their cessation of hostilities agreement of Sept 19 and "make it a reality once again".

"I think this is the best way out of this very difficult humanitarian and military situation in which the Syrians find themselves in today," he said.

The dramatic situation in rebel-held eastern Aleppo and "extremely heavy aerial bombardment" had "overshadowed" the meeting of the group which links major and regional powers.

"It is estimated that as many as 600 wounded cannot be provided with adequate treatment," Ramzy said, noting that the rebel-held sector of some 275,000 had just 35 doctors and scant medical supplies.

Hundreds of medical evacuations are the "utmost priority at this point", he said. There were also "severe shortages" of water and electricity and many bakeries remain closed.