The French president, François Hollande, has urged Syria's divided opposition to form a provisional government, saying Paris would give it official recognition.
The announcement on Monday came as Syrian fighter plane attacks on eastern suburbs of Damascus killed at least 60 people, according to opposition activists.
Hollande's intervention was aimed at increasing pressure on Syria's president, Bashar al-Assad but it also revealed differences with other western capitals.
American officials said the announcement was premature. "We're nowhere near that yet," one said.
Washington and London have been more guarded in their dealings with Syrian opposition groups which they see as too fractured and ineffective to form an alternative government.
"France asks the Syrian opposition to form a provisional government, inclusive and representative, that can become the legitimate representative of the new Syria," Hollande said, at a meeting of French ambassadors at the presidential palace. "France will recognise the provisional government of Syria once it is formed."
The Socialist president went on: "We are including our Arab partners to accelerate this step", but did not say whether he had their agreement. The Arab League is trying to encourage opposition factions to sign up to a common transition plan for a post-Assad Syria but the main exile group, the Syrian National Council, has been reluctant to take part, fearing a dilution of its influence.
While Britain and the US have distanced themselves from the SNC, seeking closer ties with internal rebel elements, France has remained a strong backer.
Egypt's new leader, Mohamed Morsi, has launched his own peace initiative in an effort to break the deadlock at a time of rising death tolls across Syria. He is due in Iran on Thursday in a significant sign of rapprochement between the two countries, and a step towards bridging Sunni-Shia differences in policy towards Damascus.
Morsi's participation at the summit of the Non-Aligned Movement of developing countries in Tehran will mark the first visit by an Egyptian leader since the 1979 Islamic revolution, and a substantial change from the foreign policy of the late dictator, Hosni Mubarak.
His proposal, first put forward at a meeting this month in Mecca of the Organisation of Islamic Cooperation, is to form a contact group made up of Egypt, Saudi Arabia, Turkey and Iran, bringing together the most powerful Sunni backers of the Syrian rebels with Assad's only significant ally in the region, the Shia regime in Tehran. All four countries initially agreed to hold a foreign ministers meeting in Cairo this week, diplomats said, but it was postponed because of the NAM summit in Iran.
Before his Tehran trip, the Egyptian leader is to hold talks in Beijing on Tuesday with the Chinese government which has hitherto supported Russia in opposing punitive measures against the Assad regime at the UN security council.
"Part of the mission is in China, part of the mission is in Russia and part of the mission is in Iran," Morsi's spokesman, Yasser Ali, said. It is not clear whether the Egyptian president will visit Russia as part of the initiative. Western officials say any attempt to broker peace in Syria will hinge on the role of Moscow, the Assad regime's principal sponsor and arms supplier. They argue that without Russian pressure, Assad is unlikely to give up his efforts to crush the insurgency.
"Given how desperate the situation is and the need for some movement on the political front it's a welcome initiative," Harling said. "In the past, the US opposed any participation of Iran in the contact group, but it makes sense to include Iran in any negotiated transition. Tehran has much to lose, and it can cause damage in the region if it is excluded. It is just diplomatic common sense."
Assad met Iranian officials in Damascus on Sunday and was quoted on Syrian state media as saying his regime would carry on fighting "whatever the price." The intensity of the fighting has dramatically increased in recent weeks culminating in a government offensive on Daraya on the south western edge of Damascus.
Various opposition claims have put the death toll in the town at between 300 and 600, many of them civilians, from three days of heavy shelling and then a group attack on Saturday, when troops and allied militiamen when from door to door.
If the reports are verified, it would be the worst massacre of the 17-month long conflict, which began in March last year with mostly peaceful anti-regime protests. Official restrictions on independent press coverage make it hard to confirm the casualty figures but independent witnesses spoke of seeing scores of bodies in the town and video footage which emerged yesterday showed mass burials.
Video footage from Damascus showed a Syrian military helicopter fall to the ground in flames. The Syrian official news agency confirmed the crash but gave no details.As the civil war continued to intensify, 9,000 Syrian refugees were yesterday reported to be stuck at the Turkish border unable to cross because of a shortage of accomodation. Turkish officials said that new shelters should be ready for them over the course of the coming week and that they would meanwhile be given humanitarian relief supplies on the Syrian side of the border.
A Turkish cameraman captured while reporting from Syria for the US-funded al-Hurra television channel, was shown on Monday on a pro-government Syrian TV channel, saying he had been seized by Syrian soldiers in the northern city of Aleppo. Cuneyt Unal crossed into Syria last week with three other journalists, including Mika Yamamoto, who was killed in Aleppo a day later. A Jordanian journalist, Bashar Fahmi, is still missing.