Russia is proposing a UN resolution urging immediate implementation of the US-Russia ceasefire agreement.
The United Nations Security Council is set to vote on rival draft resolutions on Syria - a French text requiring an end to air strikes and military flights over Aleppo city and a Russian text that is similar but does not include that demand.
The French draft resolution appears doomed to be vetoed by Russia. Moscow's text is effectively the French draft with Russian amendments that put the focus back on a September 9 US-Russia ceasefire deal, which is annexed to the draft.
"This is a cynical attempt to divert attention away from the bombing of Aleppo," British UN Ambassador Matthew Rycroft said of the Russian draft.
The 15-member council has been negotiating for a week on a French text. A Saturday vote on that was called after French Foreign Minister Jean-Marc Ayrault visited Moscow on Thursday and the US on Friday to discuss the resolution.
Moscow then proposed its own draft and said it would be put to a vote immediately after the vote on the French draft, which is likely to be blocked by Russia because it "demands that all parties immediately end all aerial bombardments of and military flights over Aleppo city".
Syrian President Bashar al-Assad's forces, backed by Russian war planes and Iranian support, have been battling to capture eastern Aleppo, the rebel-held half of Syria's largest city, where more than 250,000 civilians are trapped.
"This is not a draft which is right for adoption, I have this suspicion that the real motive is to cause a Russian veto," said Russian UN ambassador Vitaly Churkin on Friday of the French text. "I cannot possibly see how we can let this resolution pass."
Security Council diplomats, speaking on condition of anonymity, said that while the Russian draft contained a lot of reasonable language, the lack of any references to ending air strikes on Aleppo was likely to be a problem.
A resolution needs nine votes in favour and no vetoes to be adopted. The council veto powers are the United States, France, Britain, Russia and China.