Russian Foreign Minister Sergei Lavrov warned on Saturday that international support for Syrian rebels would lead to "more blood" and the government could not be expected to willingly give in to its opponents.
Lavrov, whose country has vetoed three UN Security Council resolutions intended to increase pressure on Syria's government to end 16 months of violence, said Western and Arab nations should exert more influence on rebels to stop fighting.
He said "tragedy" could be imminent in the Syrian city of Aleppo, but indicated rebels would be at least partly to blame.
"Pressure must be put on everyone," Lavrov said at a joint news conference with Japanese Foreign Minister Koichiro Gemba after talks in the Black Sea resort of Sochi, President Vladimir Putin's summer base.
"Unfortunately, our Western partners prefer to do something a bit different and essentially, along with some countries neighbouring Syria, encourage, support and direct the armed fight against the regime," he said.
"The price of all this is still more blood."
In the wake of the Security Council vetoes by Russia and China, the United States has said it will seek ways to trackle the crisis outside the UN.
Gemba said it was "very serious moment" in Syria and it was primarily up to the government to stop the bloodshed.
"The position of the Russian side has great influence, and there is also the voice of the international community. We are counting on a constructive Russian position," he said, speaking through an interpreter.
Lavrov said Russia was calling on the government to "take the first steps" but that the rebels should not take advantage of any such government actions by occupying cities and towns.
"The city of Aleppo is occupied by the armed opposition and the next tragedy is brewing there, as I understand it," he said.
"Well-armed opposition groups are occupying cities, intending to create some sort of buffer zones for a transitional government. How can one expect that the Syrian government will say, 'Yes, go ahead, overthrow me,'" he said.
"This is unrealistic — not because we are holding onto the regime but because it just doesn't work," he said.