Russia said the chances of Syrian President Bashar al-Assad staying in power were growing "smaller and smaller", as fighting on Sunday in southwestern Damascus shut a main highway from the capital.
Assad has long counted Moscow as an ally and Prime Minister Dmitry Medvedev's remarks were the most vocal Russian statement yet that his days may now be numbered, although they come after predictions from France, an avowed enemy, and from neighboring Jordan that the Syrian president's downfall is not imminent.
"I think that with every day, every week and every month, the chances of his preservation are getting smaller and smaller," Medvedev said, according to the transcript of an interview in Russian with CNN that was released by his office.
"But I repeat again, this must be decided by the Syrian people. Not Russia, not the United States, nor any other country," said Medvedev, whose administration has criticized Western, Turkish and Gulf Arab support for Syria's rebels.
"The task for the United States, the Europeans and regional powers ... is to sit the parties down for negotiations, and not just demand that Assad go and then be executed like Gaddafi or be carried to court sessions on a stretcher like Hosni Mubarak."
Russia has been Assad's most important ally throughout the 22-month-old Syrian conflict, which began with peaceful street protests and evolved into an armed uprising against his rule.
The mainly Sunni Muslim rebels have seized territory in the north of the country, including several border crossings, and have challenged Assad's control over Syria's main cities.
But Assad's air power and army, whose senior ranks are dominated by his Alawite minority, have stemmed rebel advances.
France said on Thursday there was no sign Assad was about to be overthrown, reversing previous statements that he could not hold out long, and Jordan's King Abdullah said Assad would consolidate his grip for now.
"Anybody who is saying the regime of Bashar has got weeks to live really doesn't know the reality on the ground," Abdullah said in Davos on Friday. "They still have capability, so I give them a strong shot at least for the first half of 2013."