Russia has asked Syria to put its chemical weapons stockpiles under international control and then have them destroyed, in an attempt to avoid US military strikes.
Foreign Minister Sergei Lavrov said the offer was made during talks with his Syrian counterpart, Walid Muallem, who welcomed the initiative.
The US said it was sceptical, but would have a "hard look" at the plan.
The US accuses Damascus of war crimes, allegations denied by the regime.
US Secretary of State John Kerry, in Europe to garner support for the military action, inadvertently started the talk of Syria giving up its chemical weapons early on Monday.
When asked at a news conference whether there was anything Syrian President Bashar al-Assad could do to avoid military action, Mr Kerry replied that he could hand over his entire stockpile of chemical weapons within the next week.
US officials subsequently clarified that Mr Kerry was making a "rhetorical argument" rather than a serious offer.
However, Mr Lavrov later revealed in a news conference that he had urged Mr Muallem to "not only agree on placing chemical weapons storage sites under international control, but also on their subsequent destruction".
He said he had also told Mr Muallem that Syria should then fully join the Chemical Weapons Convention.
Mr Muallem told reporters through an interpreter that Syria welcomed the initiative and praised Russia for "attempting to prevent American aggression against our people".
Mr Kerry and Mr Lavrov spoke on the phone after the Russian proposal was put forward, but US officials sounded a cautious note over the plan.
White House spokesman Jay Carney said the US government would study the proposal, but had scepticism over the credibility of the Assad regime.
"In an interview earlier, Assad refused to even acknowledge that he has chemical weapons. Of course, the whole world knows he does," said Mr Carney.
He promised that the US would continue to push for strikes because the credible threat of military action was vital in putting pressure on the Assad regime.
US allies have also reacted cautiously:
- UK Minister David Cameron said the destruction of the weapons would be a "huge step forward", but warned that it should not be used as a "distraction tactic"
- French Foreign Minister Laurent Fabius called on Mr Assad to make "rapid, serious and verifiable" commitments to the plan
- German Chancellor Angela Merkel said it was an "interesting proposal" but added that she hoped real action would follow
'Pay the price'
Moscow has been Mr Assad's main international ally throughout Syria's two-and-a-half-year civil war.
Russia has blocked three resolutions against Syria in the UN Security Council, and has dismissed US claims that Mr Assad's forces carried out a chemical attack in Damascus on 21 August, killing 1,429 people.
Mr Assad's government blames the attack on rebels fighting to overthrow him, in a conflict that the UN says has claimed some 100,000 lives.
The UN sent weapons experts into Damascus to investigate the attack.
UN Secretary General Ban Ki-moon said on Monday that if the experts concluded chemicals had been used, he would consider asking the Security Council to approve a "safe zone" in Syria where the weapons could be destroyed.
Meanwhile, the Syrian leader gave an interview to US network PBS in which he warned the US against intervention, saying the Middle East was "on the brink of explosion".
"You're going to pay the price if you're not wise with dealing with terrorists. There are going to be repercussions," he said.
"The government is not the only player in this region. You have different parties, different factions, different ideologies. You have everything in this decision now."
Mr Assad did not explain whether his comment was a threat that Syrian-backed groups such as Hezbollah would launch retaliation, or a warning that strikes would bolster al-Qaeda-linked groups.
He also denied using chemical weapons saying there was "no evidence" to hold his government responsible for the 21 August attack.
US President Barack Obama has cleared his schedule this week to focus all his attention on building support for the Syrian intervention.
He has acknowledged he faces a "heavy lift" to win congressional backing.
A poll carried out by ABC and the BBC on Friday suggested more than 230 of the 433 members in the House of Representatives were either opposed or likely to oppose strikes.
Just 44 representatives said they would support or were likely to support action, and a large proportion are still undecided on the issue.
Many US politicians and members of the public remain concerned that military action could draw the nation into a prolonged war and spark broader hostilities in the region.