MOSCOW — Russia’s foreign minister, Sergey V. Lavrov, said on Thursday that Syria needed a period of political transition but reiterated Moscow’s resistance to any plan being imposed by the international community.

“In order to overcome the Syrian crisis and to finally establish stable rights and norms which satisfy all groups in the Syrian population, it is necessary to have a transitional period, this is obvious,” Mr. Lavrov said at a news conference here in Moscow.

Mr. Lavrov’s comments came ahead of an “action group” meeting in Geneva on Saturday at which Kofi Annan, the United Nations and Arab League special envoy, could put forward a proposal for a national unity cabinet that includes opposition figures.

Mr. Lavrov said that Russia has not agreed to any new version of Mr. Annan’s faltering cease-fire plan and criticized diplomats for leaking details of the process to the press.

“There are no agreed-upon plans, work continues on a possible final document,” he said, adding that a meeting of experts will convene in Geneva on Friday.

Hints of Mr. Annan’s possible route to a diplomatic compromise emerged Wednesday when Reuters quoted unidentified diplomats as saying Russia and other powers supported his idea of a Syrian government of national unity that would include opposition figures but exclude those whose participation would undermine it — language that clearly was meant to refer to President Bashar al-Assad. But details were vague.

Part of the purpose of the meeting, a diplomat based in Geneva said, speaking on the condition of anonymity, is to uncouple the process of achieving a cease-fire from the increasing demands that Mr. Assad’s government be held to account for human rights abuses, which a United Nations panel said Wednesday have continued on “an alarming scale.”

“I consider it a sign of an unscrupulous approach to diplomacy that there are leaks to the press about certain formulas, certain ideas, that are being recommended as part of a final document by specific countries,” Mr. Lavrov said.

Russia has adamantly opposed any transition plan conditional on Mr. Assad’s departure and has insisted that opposition figures must negotiate with the government if the crisis is to be resolved. Mr. Lavrov reiterated that position in his comments on Thursday.

“We will not support and cannot support any interference from outside or any imposition of recipes,” Mr. Lavrov said. “This also concerns the fate of Bashar al-Assad,” the Syrian president.

Sergei A. Karaganov, the dean of the department of international economics and foreign affairs at the Higher School of Economics in Moscow, said it would be unrealistic to expect Russia to take an active part in implementing a transition plan.

“Russia is not willing to be responsible for the bloodshed which is continuing there, and we will not play an active role in getting Assad out,” Mr. Karaganov said.

Mr. Karaganov said Russia might agree to support the formation of a coalition government, as long as it did not include figures linked to armed resistance, but added that such a process would have little substance or real effect. “We are involved in the diplomatic process, but we are not involved in trying to solve the Syrian problem one way or another,” he said. “Many of our experts believe it is unsolvable.”

Mr. Annan, whose peace plan is in danger of collapse, announced in a statement on Wednesday that he was convening an “action group” meeting of influential countries in Geneva on Saturday in an effort to revive the plan.

But the announcement came only after Mr. Annan had made concessions over which countries would attend. Conspicuously absent from the list of the nations invited were Iran, the strongest regional ally of Mr. Assad, and Saudi Arabia, a prominent supporter of Mr. Assad’s enemies.

Mr. Annan, who had said he wanted the Iranians to be part of such a meeting, offered no explanation for why they were not invited. Asked about it later, the chief United Nations spokesman, Martin Nesirky, told reporters in New York that Mr. Annan “has been clear about the need for Iran to be part of the solution” and that Mr. Annan would brief the Iranians about the outcome of the Geneva meeting.

Mr. Nesirky declined to comment on speculation that Hillary Rodham Clinton, the American secretary of state, had threatened to cancel her participation if Iran were invited.

There was no immediate comment from Iran on its exclusion from the Geneva meeting. But Tehran’s ambassador to the United Nations, Mohammad Khazaee, said that Iran supported Mr. Annan’s peace plan and that “a very important fact that cannot be ignored by anybody is the influence and constructive role that the Islamic Republic of Iran has in the region.”

“So if some powers do not want to benefit from this influence and constructive role, that’s their problem,” he continued. “And this is another indication of their actually neglecting the realities on the ground.”

The aim of the meeting is to “identify the steps and measures to secure full implementation” of Mr. Annan’s six-point plan and to bring “an immediate cessation of violence in all forms,” Mr. Annan said in the statement, released at the United Nations’ offices in Geneva. The meeting will also seek to unite the countries behind proposals for a Syrian-led political transition “that meets the legitimate aspirations of the Syrian people,” the statement said.

Along with Mrs. Clinton, Mr. Lavrov of Russia will attend, as well as the foreign ministers of Britain, China and France, the other permanent members of the Security Council. Also invited are emissaries from Iraq, Kuwait, Qatar, Turkey, the European Union and the Arab League, as well as Ban Ki-moon, the United Nations secretary general.

The compromise formula, diplomats in Geneva said, was to limit attendance from the Middle East to countries that held a position with the Arab League: Iraq as head of the league’s summit meeting, Kuwait as head of its Council of Foreign Ministers and Qatar as head of its follow-up committee on Syria.

Mr. Annan has repeatedly warned that the conflict, which began as a peaceful Arab Spring opposition movement against Mr. Assad in March 2011, is threatening to plunge Syria and its neighboring countries into a sectarian conflagration.

The outcome will partly depend on whether the United States and Russia can bridge their differences over Syria. The United States has demanded that Mr. Assad step down. Russia, the main military supplier to Mr. Assad’s government, has rejected any solution in which political change in Syria is imposed by outside powers.

Ellen Barry reported from Moscow, Nick Cumming-Bruce from Geneva, and Rick Gladstone from New York. This article has been revised to reflect the following correction:

Correction: June 28, 2012

An earlier version of this article incorrectly stated that the Russian foreign minister, Sergey V. Lavrov, was speaking in Tunis. He was in Moscow. (Copyright 2012 The New York Times Company 06/29/12)