US remark prompts potential U-turn on Syria

He added: "We are calling on the Syrian leadership to not only agree on placing chemical weapons storage sites under international control, but also on their subsequent destruction."

His Syrian counterpart, Walid al-Moallem, who was in the Russian capital for talks, told press shortly afterward: "Syria welcomes the Russian proposal out of concern for the lives of the Syrian people, the security of our country and because it believes in the wisdom of the Russian leadership that seeks to avert American aggression."

The idea is said to have originated in an off-the-cuff remark by US secretary of sate John Kerry at a press briefing in London earlier the same day.

Kerry was in the UK after also visiting St Petersburg, Vilnius and Paris to make the case for US-led military strikes on Syria.

He said in London the US intended to launch "unbelievably small, limited" strikes in response to Syria's alleged use of sarin gas to kill hundreds of civilians on 21 August.

Asked by a US reporter if there is anything Syria could do to avert military action, Kerry replied: "Sure. He could turn over every single bit of his chemical weapons to the international community in the next week. Turn it over, all of it, without delay, and allow a full and total accounting for that. But he isn’t about to do it, and it can’t be done, obviously."

A state department spokeswoman, Marie Harf, later told press in Washington that "he was speaking rhetorically about a situation we thought had very low probability of happening."

She noted the US will study details of the Russian proposal.

But she added, referring to Syrian leader Bashar al-Assad: "We don’t want this to be another stalling exercise … We have serious, deep scepticism about this latest statement."

Some commentators say it is unlikely the proposal came out of the blue, because al-Moallem would require top-level clearance from Damascus to approve it.

US President Barack Obama also told CNN that he had floated the idea at the G20 summit in St Petersburg last Friday. He told the NBC broadcaster: "You have to take this with a grain of salt initially, but … this represents a potentially positive development."

For his part, French foreign minister Laurent Fabius, the US' main ally on Syria intervention, said in a statement on his website the Russian proposal "merits a precise study."

He said it might fly if al-Assad backs it "without delay" and if it is done via a UN Security Council resolution which spells out a precise timetable and contains "firm" sanctions on non-compliance.

He added that whoever ordered the 21 August attack must face justice at the International Criminal Court in The Hague.

British leader David Cameron, who also supports military action, but whose plan to join the US-led military coalition was recently blocked by MPs, took a similar line.

He told parliament on Monday: "It would be a big step forward and should be encouraged. But he added: "We have to be careful ... to make sure this is not a distraction tactic."

The new initiative comes as Obama gets set for a Congress vote authorising the use of force.

His national security advisor, Susan Rice, in a speech at the New American Foundation, a think tank in New York, continued to advocate intervention on Monday.

Referring to a statement signed at the G20 meeting, and a subsequent statement by EU foreign ministers in Vilnius, which spoke of a "clear and strong response" to the 21 August incident, she claimed the texts amount to: "unequivocal public support for anticipated US military action."

She noted that Germany, Lithuania, Latvia, Hungary, Croatia, Estonia, Denmark, Romania, and Qatar added their names to the G20 statement in recent days.

Meanwhile, Kerry reassured the British public the "special relationship" between the UK and the US is intact despite Cameron's failure to win MPs' backing for action.

He said: "The relationship between the United States and the United Kingdom has often been described as special, essential. And it has been described thusly, quite simply, because it is."

He added: "Our bond … is bigger than one vote. It’s bigger than one moment in history. It’s about values. It’s about rules of the road."