PARIS (Reuters) - Backers of the Syrian opposition appeared resigned to the fall of eastern Aleppo on Saturday, with the United States urging Russia to show “grace” when officials meet in Geneva to try to reach a deal for civilians and fighters to leave the city.

U.S. Secretary of State John Kerry (2ndL) and France's Foreign Minister Jean Marc Ayrault (2ndR) attend a meeting on Syria, in Paris, France, December 10, 2016. REUTERS/Thibault Camus/Pool

Syrian government and allied forces have in the last two weeks driven rebels from most of their territory in what was once Syria’s most populous city.

The rebels have controlled the eastern section since 2012, and President Bashar al-Assad said in an interview published on Thursday that retaking Aleppo would change the course of the civil war across the whole country.

Critics of the operation have warned that thousands of civilians risk being caught in the crossfire and have repeatedly called on Syrian government forces backed by Russian air power to accept a ceasefire to allow civilians and rebel fighters to leave to safer areas.

Speaking in Paris after a meeting of countries that oppose Assad, including France, Britain, Turkey and Saudi Arabia, U.S. Secretary of State John Kerry showed little optimism for U.S. and Russian talks in Geneva later on Saturday.

“Our teams are meeting in Geneva today in order to flesh out details of a possible way of trying to save lives. Russia and Assad have a moment where they are in a dominant position to show a little grace,” Kerry told reporters.

“I believe there could be a way forward but it depends on big, magnanimous choices from Russia ... and insistence of Russia on the Assad regime,” he said.

Moscow and Washington have discussed a ceasefire to let civilians escape eastern Aleppo and aid enter. Russia also wants the United States to urge rebel fighters to abandon their territory and accept transport out.

“Fighters ... don’t trust that if they agreed to leave to try to save Aleppo that it will save Aleppo and they will be unharmed and free to move where they are not immediately attacked,” Kerry said, adding that Geneva talks had to set some guarantees for rebels.

The meeting in Paris, also attended by Riad Hijab, the main opposition coordinator, underscored the powerlessness of Syrian opposition supporters, as well as some divisions between them.

Beyond the issue of humanitarian access, France’s Foreign Minister Jean-Marc Ayrault said Moscow and Damascus needed to realize that the fall of Aleppo would not end the war and that negotiations based on U.N. Security Council resolutions agreed in Dec. 2015 should be revived to find a political solution.

More than five years of war in Syria have killed more than 300,000 people and made more than half of Syrians homeless.

“What peace do they want? The peace of cemeteries?,” Ayrault said. “Negotiations must start again... The opposition is ready to negotiate without preconditions.”