BEIRUT, Lebanon -- Lakhdar Brahimi, the international envoy on a mission to Damascus seeking an end to the escalating civil conflict in Syria, said Thursday that a transitional government with full executive authority should be established, perhaps within months, and should rule the country until elections could be held.
Mr. Brahimi did not say who would serve in such a government, and he offered no details about the role that President Bashar al-Assad would play -- if any -- during a transitional period. But his comments suggested that if Mr. Assad remained in the country, he would retain none of his authority.
"All the powers of government should be with this government," Mr. Brahimi said of the proposed transitional authority.
His comments to reporters in Damascus were his most detailed since he traveled Sunday to Syria, where he met with Mr. Assad and Syrian opposition members in an effort to revive hopes of a political solution to the nearly two-year-old crisis. But even as Mr. Brahimi and other international diplomats warned Thursday of the high cost Syrians would pay if his efforts failed, there was no immediate sign of a new diplomatic formula that would be acceptable to both the government and its opponents.
"The situation is bad and worsening," Mr. Brahimi said. "The Syrian people are suffering unbearably. We do not speak in a vacuum about theoretical things."
Over the past month, Mr. Brahimi, as the special Syria representative from the United Nations and the Arab League, has consulted extensively with the United States and Russia in hopes of fulfilling an accord reached in Geneva this summer calling for dialogue between Syria's government and the opposition.
As a Syrian government delegation met with Russia's top diplomats in Moscow on Thursday, a spokesman for the Russian Foreign Ministry, Aleksandr K. Lukashevich, said no specific plan was under discussion.
Russia, a leading ally of the Assad government, has long pointed to the Geneva agreement, which calls for the creation of a transitional government and for talks between the antagonists, as the only acceptable basis for resolving the conflict. However, the agreement does not address Mr. Assad's fate, which is a crucial problem because many in the opposition say he must step down as a precondition for talks.
In Damascus on Thursday, Mr. Brahimi also denied that he had proposed a specific plan, as many opposition members had asserted in recent days. And he said that the United States and Russia had not reached any agreement that he was pressing Mr. Assad to accept. "I wish there was a U.S.-Russia proposal for me to sell," he said, adding: "I did not come here to sell."
The envoy said that the Geneva framework "includes elements that are sufficient for a plan to end the crisis in the next few coming months," mentioning a peacekeeping force to monitor a cease-fire and the establishment of a transitional government. He said that the transition "should not be allowed to lead to the collapse of the state and its institutions."
Mr. Brahimi's comments were met with pessimism by members of the largest opposition coalition, who have long said that any arrangement that left Mr. Assad in the country was unacceptable. They have also called for the dismantling of state institutions tied to repression by the government, especially the security and intelligence services. As insurgent groups make gains against the Syrian military, the political opposition has shown even less willingness to compromise.
"His initiative is very late, and it is very much detached from what's actually happening on the ground and on the battlefield," said Ahmad Ramadan, a coalition member who is in Turkey. "We will not discuss any transitional government before Bashar al-Assad steps down."
In Washington, a State Department spokesman, Patrick Ventrell, on Thursday praised efforts to produce a peaceful transition but ruled out any role for Mr. Assad in the process.
Frederic C. Hof, who served as a special adviser on Syria to the State Department, said in an e-mail that Mr. Brahimi's efforts amounted to "a long shot."
"Assad is not yet persuaded that he needs to yield power and get out," Mr. Hof said. "There is no solution that involves him sticking around, even as a figurehead."
Even a pact that requires Mr. Assad's allies and Syrian opposition forces to simply agree to negotiate would be a hard sell, said Dmitri V. Trenin, the director of the Carnegie Moscow Center.
This year, he said, influential policy makers in Moscow favored a process like the one that led to the Dayton Accords to end the Bosnian war of the 1990s. "Bring them together, close the door and don't let them out until they reach an agreement," he said.
But Mr. Trenin said he had serious doubts that either Moscow or Washington could induce the two sides in Syria to sit down at the table. "Frankly, I see very little leverage that Russia has over Assad," he said. "Even if the United States were prepared to lean hard on the opposition, or push them toward some kind of negotiation, I do not see the gulf states or the Turks backing that move."
In recent weeks, said Mr. Lukashevich, the Foreign Ministry spokesman, Moscow has ratcheted up its diplomacy in an effort to "intensify dialogue, not only with the government but also with the opposition groups."
Top Russian officials met Thursday in Moscow with Syria's deputy foreign minister, Faisal al-Meqdad. Mr. Brahimi will meet with the Russian foreign minister, Sergey V. Lavrov, in Moscow on Saturday.
Mr. Lukashevich said Russia was open to talks with Syria's national opposition coalition, which has been recognized by many Western governments as representing the Syrian people.
"We are not rejecting this dialogue," he said. "On the contrary, we are holding it very vigorously with all opposition groups who are also interested in getting better insight into the Russian approach."
"It is obviously another question when and at what level they will take place," he said.
Kareem Fahim reported from Beirut, and Ellen Barry from Moscow. Hwaida Saad contributed reporting from Beirut, Hala Droubi from Dubai, United Arab Emirates, and Eric Schmitt from Washington.
This article originally appeared in The New York Times.