MOSCOW -- Russia's foreign minister, Sergey V. Lavrov, said on Saturday that there was "no possibility" that President Bashar al-Assad of Syria could be persuaded to leave and that the opposition's insistence on his departure as a precondition for peace talks would only cost "more and more lives of Syrian citizens" -- suggesting slender hope for a breakthrough in negotiating an end to a conflict that has already killed more than 40,000.
Moscow has made a muscular push for a political solution in recent days, sending signals that the Kremlin, one of Mr. Assad's most crucial allies, sees an urgent need for political change. But even as an international consensus forms around the notion of a transitional government, it has snagged on the thorny question of what role, if any, Mr. Assad would play.
After talks on Saturday in Moscow with Lakhdar Brahimi, the United Nations and Arab League envoy on Syria, Mr. Lavrov said that Moscow could not force Mr. Assad to leave power.
"He has repeatedly said, both publicly and privately, including during his meeting with Lakhdar Brahimi not long ago, that he has no plans to go anywhere, that he will stay in his post until the end, that he will, as he says, protect the Syrian people, Syrian sovereignty and so forth," Mr. Lavrov said. "There is no possibility of changing this position."
Mr. Lavrov responded icily on Saturday to the leader of the main opposition coalition, Sheik Ahmad Moaz al-Khatib, who said he would not travel to Moscow to meet with Russian leaders and asked Moscow to publicly apologize for its pro-government position.
Mr. Lavrov said he would agree to meet with Mr. al-Khatib in an Arab country.
"I know that Mr. Khatib is probably not very experienced in politics," Mr. Lavrov said. "If he aspires to the role of a serious politician, he will nonetheless understand that it is in his own interests to hear our analysis directly from us."
There have been signs of changes in the long standoff over Syria in recent weeks. Russia acknowledged that government forces are losing territory and distanced itself from Mr. Assad. In a televised question-and-answer session, President Vladimir V. Putin said Russian leaders "are not preoccupied by the fate of Assad's regime" and that after 40 years of rule by one family, "undoubtedly there is a call for change."
But Moscow has watched the Arab uprisings with mounting anger, arguing that the West was encouraging extremist groups to rebel against their leaders, and vehemently opposed any international intervention in Syria as a matter of principle.
Developments on the battlefield have accelerated the pace of diplomacy.
Mr. Brahimi, a former Algerian freedom fighter who is viewed sympathetically in Moscow, this week recommended that a transitional government should be established, perhaps within months, and that it should rule the country until elections could be held.
Like Russia, Mr. Brahimi hopes to structure a political settlement on the basis of an international agreement reached last summer in Geneva, which envisages a transitional government and peacekeeping force. The Geneva document omits two elements that Russia and China opposed: it does not address Mr. Assad's fate, nor does it invoke the United Nations's tough Chapter VII sanctions against the Syrian government, which authorize economic measures and, if necessary, military action.
On Saturday, Mr. Brahimi said that it might be necessary to "make some small changes to the Geneva agreement," though he did not say what they were. He warned that if a political solution was not possible, Syria will be overrun by violence -- envisioning the panicked flight of a million people across Syria's borders into Jordan and Lebanon.
"If the only alternatives are hell or a political process, then all of us have to work continuously toward that political process," he said. "It is difficult, it is complicated, but there is no other choice."
Russia has set the stage for forward momentum, announcing a trilateral gathering to discuss Syria in mid-January between the United States, Russia and Mr. Brahimi. Russia's top middle east envoy, Deputy Foreign Minister Mikhail Bogdanov, referred to this group with the friendly nickname the "Three B's," because it includes himself, Mr. Bogdanov, and Undersecretary William Burns, a former ambassador to Moscow.
Moscow may see these current talks as a chance to rebuild its prestige in the Arab world, where Russia historically strong alliances have been badly damaged by the standoff over Syria. Mr. Lavrov bridled on Saturday when a reporter from an Arabic news channel asked him to comment on criticism that Russia is "a participant in the Syrian conflict" because it continued to fulfill weapons contracts with Syria after the outbreak of violence.
The accusation, Mr. Lavrov said, "is so far from the truth that there's no way to comment on it." He said Russia does not supply the Syrian government with offensive weapons, and that much of the Syrian arsenal dates back to the Soviet era. He also said that the opposition was receiving a far more deadly flow of weapons and aid.
Unlike some other countries, he said, "we do not have the dozens and hundreds of representatives of the Russian special forces" in and around Syria. "It's possible to speak about direct participation in the conflict," he said, "but it doesn't apply to the Russian Federation."
This article originally appeared in The New York Times.