The US and Russia have reportedly tabled a proposal to rebels in Aleppo that would offer safe passage from the city for fighters, their families and other civilians.
Three opposition officials with rebel groups in Aleppo gave the news to reporters in Geneva.
Russia and the US have been meeting in the Swiss city to seek a solution to the fighting and the humanitarian crisis it has generated.
The situation in Aleppo
The Russian-backed Syrian military and its allies have captured swathes of rebel-held eastern Aleppo in a ferocious military campaign.
Rebel fighters and tens of thousands of civilians have been squeezed into an ever-shrinking enclave in the east of the city.
New army gains on Sunday south of Aleppo’s historic citadel appear to bring victory closer for the government forces.
What Russia says
Russia, however, has denied that any deal has been reached.
Diplomats say reports of the proposal do not “necessarily correspond with reality”.
Moscow’s RIA news agency has quoted Deputy Foreign Minister Sergei Ryabkov as saying that Russia is working to create the necessary conditions for the safe extraction of people from Aleppo.
“The issue of withdrawing militants is the subject of separate agreements. This agreement has not yet been reached, largely because the United States insists on unacceptable terms,” Ryabkov is quoted as saying.
He added that the talks in Geneva would continue.
What the rebel groups say
The groups in Aleppo have yet to respond to the proposal.
It promises rebel fighters a “secure” and “honorable” withdrawal from the city, the rebel officials say.
What has the UN said?
The office of the UN Special Envoy to Syria, Staffan de Mistura, says it has no comment for now on the report.
What happens if the proposal is accepted?
If the rebels accept the proposal, it would restore Syrian President Bashar al-Assad’s full control over rebel-held areas of eastern Aleppo.
This could be seen as his biggest victory so far in the civil conflict that has shattered his country.
Agreement from all sides would end four years of fighting in the city, as well as months of siege and intense bombardment.
This has created a humanitarian crisis, particularly in rebel territory in the city that has now shrunk to a small pocket crammed with civilians.
The terms of the proposal
The Syrian government and its allies would guarantee safe passage for fighters, their family members and other civilians from the city.
A draft of the proposal sent to Reuters from two of the rebel officials said the Syrian government and its allies would give a public guarantee that fighters and civilians leaving the city would not be detained or harmed.
The safety of civilians who wish to remain in the city would also be guaranteed.
The plan would also require fighters from the jihadist group Jabhat Fateh al-Sham – formerly known as the Nusra Front – to head to the northwestern province of Idlib.
However, fighters from other groups would be allowed to go to other destinations, including areas near the Turkish border to the northeast of Aleppo.
These are held by groups fighting under the banner of the Free Syrian Army.
Implementation would be carried out over a 48-hour period. UN oversight will be sought.
Fighters will be allowed to take light weapons with them but must leave heavy weapons behind.
Rebel groups in the city have previously said they would not leave eastern Aleppo.
At the same time, they have been demanding safe passage for civilians who wish to leave for areas to the north of Aleppo near the border with Turkey.
The ISIL attack on Palmyra is threatening to inflict a serious blow on both Damascus and Moscow.
Syrian state radio is reporting the army has evacuated its positions from inside the ancient city and is redeploying them on its fringes.
Analysts warn that even if Assad defeats the main rebellion, he may still face years of guerrilla insurgency as he tries to reassert his authority.