Residents of Aleppo, the northern Syrian city besieged by President Bashar al-Assad's forces, could be just 10 days away from starvation, aid workers have warned.

Inhabitants of the eastern parts of the city are in desperate need of food and medicines and aid efforts are becoming increasingly desperate as the captive population face starvation, according to the head of the Syria Civil Defence (better known as the White Helmets).

The volunteer group, which is nominated for this year's Nobel Peace Prize and comprises roughly 3,000 volunteer rescue workers in rebel-held areas, is also said to be running out of equipment, from vehicles to diesel and gas masks.

"You cannot imagine how the situation is," said White Helmets head Raed al-Saleh.

"Doctors and the rescue workers in Aleppo are just using what's left of the equipment after bombardments to do whatever they can do."

Anti-government fighters agreed to a United Nations proposal to ensure crucial aid was delivered to the area and the wounded could be evacuated. However, the plan is being slowed by Russia and Syria's ruling government which have not yet greenlit the move, according to Jan Egeland, UN humanitarian adviser.

Freezing winter conditions are increasing the urgency of the situation, with 275,000 people estimated to be trapped in the area where the last UN food rations were distributed on November 13.

The White Helmets also told how without enough medical supplies, doctors were forced to choose which patients to treat.

"They cannot accept everyone. There are not enough materials and not enough doctors," Saleh said.

He also told how the volunteer group had depleted its equipment by 50% in the past two months.

"We have consumed all the stock of first aid kits in our centres and we have consumed all our stock of gas masks," he said. "We are concerned that within 10 days we may consume all our remaining stock of diesel which is required for the ambulances and the trucks to move."

On Monday (21 November), US President Barack Obama said he was not optimistic about the prospect of peace in the Syrian civil war saying the joint Syrian, Russian and Iranian air campaign over eastern Aleppo had made the existence of a moderate opposition impossible.

Speaking at a summit of the Pacific Rim countries in Peru (the Apec Summit), he said the coalition backing the Syrian regime in Damascus was bombing "regardless of civilian casualties".

Relentless air strikes on eastern Aleppo have left the area without a single hospital operating to full capacity, the Syrian American Medical Society said on Saturday (19 November).

The World Health Organisation (WHO) said all makeshift hospitals were out of service. But reports indicate that some of the medical facilities are still functioning, but that residents were too afraid to use them.

White House National Security Adviser Susan Rice said the US condemned the air strikes "in the strongest terms" and called on Russia to take measures to stop the violence.

The Syrian government has since rejected a UN proposal to grant autonomy to eastern Aleppo saying restoring regime rule was a matter of "national sovereignty".

Aleppo children
Children inspect rubble of damaged buildings in a rebel-held besieged area in Aleppo on 6 November, 2016 Abdalrhman Ismail / Reuters