Kofi Annan, right, Joint Special Envoy of the United Nations and the Arab League for Syria, speaks with Russian Foreign Minister Sergey Lavrov after a meeting of the Action Group for Syria at the European headquarters of the United Nations in Geneva. (Laurent Gillieron/AP)

World leaders agreed Saturday to push the Syrian government and opposition forces to begin negotiations toward a transitional government but failed to specify whether President Bashar al-Assad must be excluded.

Instead, participants at a conference in Geneva vowed to “apply joint and sustained pressure on the parties in Syria,” including “members of the present government and the opposition and other groups,” to designate representatives for the talks.

Secretary of State Hillary Rodham Clinton and her Russian counterpart, Sergei Lavrov, offered somewhat different interpretations of that mandate.

In comments to reporters, Lavrov noted that the group’s final communique includes no demand for Assad to step down. A call to exclude anyone who would undermine negotiations or a new government, contained in a draft proposal from Kofi Annan, envoy for the United Nations, did not appear in the communique.

Clinton acknowledged what she called “minor textual changes” in Annan’s proposal but said they did not affect the substance of what was decided at the meeting. “We read the results to be the same,” Clinton said. “Assad will still have to go.”

“We and our partners made absolutely clear to Russia and China that it is now incumbent upon them to show Assad the writing on the wall,” she said.

In the communique, participants also pledged their opposition “to any further militarization of the conflict,” an agreement that would seem to preclude provision of arms to either Assad or the opposition. They also agreed to additional U.N. mandates “if requested,” and demanded an immediate cease-fire from all parties and safe access for humanitarian organizations, journalists and an existing group of U.N. monitors.

Annan convened the meeting of the five permanent members of the Security Council — Britain, France and China, in addition to the United States and Russia — and Arab League leaders after acknowledging that his U.N.-backed cease-fire plan was not working. Saturday’s proposal incorporates that plan but specifies new negotiations among mutually agreed government, opposition and minority representatives and the formation of an interim government including all of them, followed by a new constitution and democratic elections.

Asked about a timetable for implementation, Annan said he would “immediately engage the government and opposition, and consult widely with Syrian society” and that he expected to visit Damascus, the Syrian capital.

In a stern statement opening the conference, Annan told the delegations that “we should never have even reached this point. Security Council resolutions have been passed, joint statements of determination issued, a peace plan agreed and commitments made. The great and the powerful in the international community have repeatedly expressed their firm backing and resolve to do what is needed.”

“Action should surely have been taken” to implement his original plan, he said, “but none has been forthcoming.” That failure, and the deteriorating situation in Syria, Annan said, “leaves you with a clear choice: either unite to secure your common interests; or divide, and surely fail each in your own individual way.”

While Clinton focused her comments on Russia’s responsibility to push Assad out of the way, the opposition’s response to the Geneva statements indicated that the United States and its allies also have their work cut out for them in convincing the opposition to drop its insistence that Assad’s guaranteed departure precede any negotiations.

“The regime is not going to cooperate on anything,” said Bassma Kodmani, head of foreign relations for the opposition Syrian National Council. “There is no successful formulation without the departure of Assad. This is a condition that is non-negotiable.”

Coverage of the conference by Sana, the Syrian government news agency, emphasized the communique’s call for Syrians to decide their own future, and Lavrov’s assurance that there was no specific call for Assad’s departure.

As diplomats met in Geneva, the London-based Syrian Observatory for Human Rights said at least 81 civilians were killed Saturday in Syria, most of them from government shelling and sniper fire in cities around the country, at least 30 of them in an explosion at a funeral procession in Zamalka, a Damascus suburb. About 20 government soldiers were also killed in clashes with opposition fighters, according to an observatory spokesman.