Welcomed proposal

The rebels who hoped to see US missiles rain down on the government denounced the idea as a plot by Putin to protect the Syrian leader.

Britain's Prime Minister David Cameron also expressed concern that the plan might be "a distraction tactic" but broadly welcomed it.

German Chancellor Angela Merkel described the Kremlin's proposal as "interesting" but added that she hoped it would be put into place quickly and not simply be used to "buy time".

And France, the only Western ally to have offered to take part in a US-led strike, said Assad must commit "without delay" to the elimination of his chemical arsenal.

United Nations chief Ban, meanwhile, called for the creation of UN supervised zones in Syria where the country's chemical weapons can be destroyed.

He told reporters he may propose the zones to the Security Council if UN inspectors confirm banned weapons were used and to overcome the council's "embarrassing paralysis" over Syria.

For his part, Assad warned earlier in an interview with US television that the United States will "pay the price" if it attacks Syria.

But US cruise missile destroyers are idling in the eastern Mediterranean, preparing for what US officials described as a limited punitive strike.

According to US intelligence, on Aug 21 a chemical attack against rebel-held suburbs of Damascus killed more than 1,400 people.

Western states and the Arab League have condemned the alleged barrage as a war crime and blamed it on Assad's government.

Obama has argued that a military strike is necessary to defend the long-established international taboo against the use of chemical weapons.

The crisis in Syria began in March 2011 and eventually degenerated into an all-out civil conflict that has killed more than 100,000 people, according to the UN.

AFP-AP