The U.N. Security Council has scheduled a vote for Wednesday afternoon on a new Syria resolution while Russia and the West remain at loggerheads over threatening sanctions against the Syrian government.
But diplomats said there is still a possibility of last-minute negotiations.
The council must decide by Friday whether to extend the mandate of the 300-strong U.N. observer force in Syria.
Russia is adamantly opposed to any mention of non-military sanctions or Chapter 7 of the U.N. Charter, which can be enforced militarily, which the U.S. and its European allies insist must be included in a new resolution.
Russia called council consultations late Tuesday on its proposed resolution but deputy ambassador Alexander Pankin said afterward that any mention of Chapter 7 or sanctions were still a "red line for Moscow."