BEIRUT (Reuters) - The United States and Russia on Sunday 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 Aleppo rebel groups told Reuters.

People walk near rubble of damaged buildings, in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

However, Russia denied that any deal had been reached, saying that reports of the proposal do not “necessarily correspond with reality”.

The rebel groups in Aleppo have yet to respond to the proposal, the opposition officials said. The proposal promised rebel fighters a “secure” and “honorable” withdrawal from the city, they said.

If rebels accept the proposal, it would restore Syrian President Bashar al-Assad’s full control over rebel-held areas of eastern Aleppo, his biggest victory yet in the civil war that has shattered his country.

The Russian-backed Syrian military and its allies have captured swathes of rebel-held eastern Aleppo in a ferocious military campaign, squeezing rebel fighters and tens of thousands of civilians into an ever shrinking enclave.

Russia and the U.S. have been meeting in Geneva to seek a solution to the fighting and the humanitarian crisis it has caused.

Moscow’s RIA news agency quoted Deputy Foreign Minister Sergei Ryabkov as saying that Russia was working to create the necessary conditions for the safe extraction of people from Aleppo and that the Geneva talks would continue.

“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,” RIA quoted him as saying.

Under the proposal, the Syrian government and its allies would guarantee safe passage for fighters, their family members, and other civilians from the city.

The rebel groups in the city have previously said they would not leave eastern Aleppo, while demanding safe passage for civilians who wish to leave to areas to the north of Aleppo near the border with Turkey.

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, and guarantee the safety of civilians who wish to remain in the city.

It would require fighters from the jihadist group formerly known as Nusra Front to head to the northwestern province of Idlib. But it would allow fighters from other groups to go to other destinations including areas near the Turkish border to the northeast of Aleppo, which are held by groups fighting under the banner of the Free Syrian Army.

Implementation would be carried out over a 48-hour period, and U.N. oversight would be sought. Fighters would be allowed to take their light weapons with them, but must leave heavy weapons behind, the proposal said.

The office of the U.N. Special Envoy Staffan de Mistura said it had no comment for now on the report.