International powers have agreed that a transitional government should be set up in Syria to end the bloodshed there but left open the question of what part President Bashar al-Assad might play in the process.
Peace envoy Kofi Annan said after talks in Geneva on Saturday that the government should include members of Assad's administration and the Syrian opposition and pave the way for free elections.
"It is for the people to come to a political agreement, but time is running out," Annan said in concluding remarks. "We need rapid steps to reach agreement. The conflict must be resolved through peaceful dialogue and negotiations."
The Geneva talks had been billed as a last-ditch effort to halt the worsening violence but hit obstacles as Russia, Assad's most powerful ally, opposed Western and Arab insistence that he must quit the scene.
The final communique said the transitional government "could include members of the present government and the opposition and other groups and shall be formed on the basis of mutual consent".
But in a victory for Russian diplomacy, it omitted language contained in a previous draft which explicitly said it "would
exclude from government those whose continued presence and participation would undermine the credibility of the transition and jeopardise stability and reconciliation".
Al Jazeera's Peter Sharp, reporting from Geneva, said that the removed text "was presumed by Russia to suggest that President Bashar al-Assad would not be able to take part in the new government. And they put their foot down".
"Now we have got a new text that says the new government would include members of the government and opposition, but they will be there by mutual consent," he said.
Sergei Lavrov, Russian foreign minister, said he was "delighted" with the result as it meant no foreign solution was being imposed on Syria.
Rebels and opposition politicians outside the country are likely to reject the presence of Assad, his family or his top aides in any transitional government.
Hillary Clinton, the US secretary of state, took a different perspective from Lavrov, saying the communique sent a clear message to Assad that he must step down.
"Assad will still have to go," Clinton told a news conference after the meeting ended. "What we have done here is to strip away the fiction that he and those with blood on their hands can stay in power."
In-depth coverage of escalating violence across Syria
Annan called the meeting afte all but admitting the failure of a six-point peace plan he drafted at the behest of the United Nations and Arab League, and which has largely been ignored by the Assad government. He stressed that the transition must be led by Syrians and meet their legitimate aspirations.
"No one should be in any doubt as to the extreme dangers posed by the conflict - to Syrians, to the region, and to the world," he said in opening remarks.
His plan for a negotiated solution to the 16-month-old conflict is the only one on the table and its failure would doom Syria to even more violence.
More than 10,000 people have been killed since the anti-Assad uprising broke out in March 2011, and the past few weeks have been among the bloodiest. Entire districts of major cities have been nearly wiped out, and both sides have been accused of committing crimes, including execution, though the government is suspected to have been behind the worst massacres.
Highlighting the deteriorating situation on the ground, Syrian government forces pushed their way into Douma on the outskirts of Damascus on Saturday after weeks of siege and shelling.
Fleeing residents spoke of corpses lying in the streets. The army also attacked pro-opposition areas in Homs, Idlib and the outskirts of Damascus, opposition activists said.
William Hague, the British foreign secretary, said Assad and his close associates could not lead any transition.
Accountability for war crimes must be part of such a process, he added in his speech to the meeting.
Hague called for the UN Security Council to start drafting a resolution next week setting out sanctions against Syria, a move that he noted put him at odds with Russia.
The foreign ministers of the council's five permanent members - Russia, the United States, China, France and Britain - all attended along with Turkey, Kuwait, Qatar, UN Secretary-General Ban Ki-moon, Arab League chief Nabil Elaraby and EU foreign policy chief Catherine Ashton.
Notably uninvited were Iran, Syria's closest regional ally, and Saudi Arabia, a foe of both Damascus and Tehran and leading backer of the rebel forces opposing Assad.
The Syrian government or opposition were both not represented.