The civil defence in Syria's rebel-held eastern Aleppo has exhausted its fuel reserve and all fuel remaining in its vehicles and equipment will run out within two days, an official in the organisation says.
The civil defence, also known as the White Helmets, is a rescue service that operates in rebel-held areas of Syria. The group draws on ambulance workers and volunteers who dig survivors and the dead out of rubble.
"All the fuel we have has finished," Ibrahim Abu al-Laith told Reuters. The only fuel left was what remained in the machines and that will not last longer than two days, he added.
The Syrian army and its allies announced the capture of a swathe of eastern Aleppo from rebels on Monday in an accelerating attack that threatens to crush the opposition in its most important urban stronghold.
Two rebel officials said the insurgents, facing fierce bombardment and ground attacks, had withdrawn from the northern part of eastern Aleppo to a more defensible front line after government advances risked splitting the rebel-held area in two.
The Syrian Observatory for Human Rights said the northern portion of eastern Aleppo lost by the rebels amounted to more than a third of the territory they had held, calling it the biggest defeat for the opposition in Aleppo since 2012.
Thousands of residents were reported to have fled. A rebel fighter reached by Reuters said there was "extreme, extreme, extreme pressure" on the insurgents. Part of the area lost by the rebels was taken over by a Kurdish militia from Aleppo.
Capturing eastern Aleppo would be the biggest victory for President Bashar al-Assad since the start of the uprising against him in 2011, restoring his control over the whole city apart from a Kurdish-held area that has not fought against him.
The war pits al-Assad, supported by Russian air power and Iranian-backed militias, against an array of mostly Sunni Muslim rebel groups, some backed by Turkey, Gulf monarchies or the United States.