MUNICH -- The leader of the Syrian opposition council, Sheik Ahmad Moaz al-Khatib, met here on Saturday with representatives of the United States and Russia -- who fundamentally disagree on how to resolve Syria's civil war -- but the meetings were separate and there was no indication, officials said, that any progress had been made toward a workable plan to bring the violence to an end.
Moscow has been encouraged by Sheik Khatib's suggestion, which he repeated here, that he would be willing to talk to Syrian government representatives under certain conditions. But European and American officials expect that offer to go nowhere now that the sheik's colleagues in the opposition have attacked it.
The side meetings at the annual Munich Security Conference seemed to confirm the fissures over Syria, including a new disagreement between the United States and some of its European allies over whether to provide rebel fighters with more powerful weapons.
Senior European officials here said Britain and France were both urging the Obama administration to stop blocking allies in the Persian Gulf, like Qatar, from providing the rebels with more sophisticated arms and intelligence assistance.
The officials say that the current Syrian stalemate means that the opposition is not winning, and that President Bashar al-Assad is not losing. An opposition with better military means could break the confidence of Mr. Assad and his allies and push him to negotiate with the opposition, the officials argue.
But President Obama, American officials here said, remains unconvinced about the positive effects of further militarizing the conflict. They pointed to his recent interview with The New Republic, in which he said, "In a situation like Syria, I have to ask, can we make a difference in that situation?" American officials fear that the advanced weapons will fall into the hands of Islamists with an international agenda who have joined the fight in Syria.
The Munich conference, in its 49th year, is considered the premier trans-Atlantic gathering for security officials and analysts.
Vice President Joseph R. Biden Jr., representing an Obama administration in its second-term transition, carefully made no news in a well-received speech designed to reassure European allies of a continuing focus on European concerns despite the American "pivot to Asia."
And while Mr. Biden implicitly criticized Russia for supporting the Assad government, he gave the Syrian opposition little hope that Washington would change its mind about allowing more sophisticated arms to flow to the rebels.
Mr. Biden repeated America's demand that Mr. Assad relinquish power, which was immediately criticized by the Russian foreign minister, Sergey V. Lavrov, as "the single biggest reason for the continuation of the tragedy in Syria." And while Mr. Biden listed the $365 million in humanitarian aid to Syrian refugees and $50 million in nonlethal assistance to the Syrian opposition provided by the United States, he promised nothing that would help turn the war in the rebels' favor.
"As the Syrian people have their chance to forge their own future, they will continue to find a partner in the United States of America," Mr. Biden said.
He also spoke about Iran, repeating the United States' assertion that it is willing to open direct, bilateral talks with Tehran over its nuclear program, but insisting that Iran must show that it is serious and that the talks will be substantive. "We're not prepared to do it just for the exercise," Mr. Biden said.
The administration has been pushing for months to hold direct talks with Iran, calculating that there is a window for diplomacy before Iran's elections in June. But in recent weeks, Iranian officials have thrown cold water on the idea. Iran has balked at setting a date or location for multilateral talks with the United States and other major powers.
In a sign of the intransigence of the conflict over Syria's future, the United Nations negotiator for the country, Lakhdar Brahimi, expressed pessimism on Friday at a panel discussion. "I am much more conscious of the difficulties, of the country being broken down day after day, than I am of a solution," said Mr. Brahimi, who also met with Sheik Khatib.
Sheik Khatib -- who directs a Syrian opposition council cobbled together with Washington's help, and pressure, to try to unify a fractured movement -- found himself struggling last week to tamp down criticism of his suggestion that he would be open to talking with representatives of the Assad government. (His terms of participating were that 160,000 prisoners had to be released and that Syrians abroad could renew their passports.)
But his own colleagues strongly objected, saying that the talks must focus on the removal of Mr. Assad. While Sheik Khatib reiterated his offer here, saying, "As a gesture of good will, we are ready to sit at the negotiating table with the regime, but we don't want their hands to be full of blood," he refused to provide any details.
He also called for the West to destroy the government's air power, which would require the direct military intervention that Washington has ruled out.
Mr. Lavrov, for his part, expressed the standard Russian position: no international military involvement, no solution by military means, an immediate cease-fire, and negotiations among all parties, including Mr. Assad. He said the biggest threat in Syria was "the possibility that the rebels get hold of the chemical weapons" currently under Mr. Assad's control.
Fighters in Syria were only vaguely aware of the Munich events. Mohamed Maarouf, a rebel commander from Idlib Province, said: "I do trust Moaz al-Khatib, but I think there was too much pressure upon him to meet the Russians. We were forced to, after the world abandoned us."
Dr. Kamal Labwani, a member of the opposition coalition, said the idea of negotiating with the government was based on a flawed premise. "They want us to consider this regime as a segment of the Syrian community, a legitimate segment that speaks on behalf of people," he said. "Well, it's not true."
Mark Landler contributed reporting from Washington, and Hwaida Saad and Anne Barnard from Beirut, Lebanon.
This article originally appeared in The New York Times.