NEW YORK (AFP) – Russia clashed once again with Western powers on Tuesday, as envoys drafted a UN resolution to add muscle to a plan to strip Syria of its chemical weapons.

U.S. President Barack Obama maintained his threat to launch military strikes against the regime of Syrian president Bashar al-Assad, even while cranking up the diplomatic pressure on Moscow.

Envoys from France, Britain and the United States launched talks on a resolution after Russia had revealed a surprise plan of its own to secure Assad’s banned weapons.

But Russia’s foreign minister Sergei Lavrov declared that any resolution under Chapter Seven of the UN charter, which authorizes enforcement measures, would be “unacceptable.”

Moscow’s UN mission called an urgent Security Council meeting, and France and Britain said they planned to introduce their motion later in the day.

Russia’s proposal on Monday was seized upon by some as a way to dismantle Syria’s nerve gas stockpile, but Western capitals remain deeply skeptical of both Moscow’s and Damascus’s intent.

And Obama’s top national security team insisted Tuesday that U.S. military action to punish Assad’s alleged use of chemical weapons was still very much on the table.

They said the White House would examine the Russian initiative while still seeking domestic congressional authorization for a limited package of missile strikes.

“We’re waiting for that proposal. But we’re not waiting for long,” U.S. Secretary of State John Kerry said.

In Paris, Foreign Minister Laurent Fabius said that France was seeking a resolution to “provide for extremely serious consequences in the event of Syria violating its obligations.”

And Britain’s prime minister David Cameron said: “I think we do need some deadlines, we do need some timetables.

“This is not about someone monitoring chemical weapons in Syria. It’s got to be about handing them over to international control and their destruction.”

Obama was due to make a major national address to a skeptical U.S. public and Congress later in the day to ask for authorization to order missile strikes to punish Assad’s regime.

U.S. intelligence alleges that on August 21, Assad’s forces fired volleys of rockets armed with sarin gas at a dozen rebel-held suburbs of Damascus, killing more than 1,400 people.

Syria said Tuesday it would cooperate with the Russian plan to place its chemical weapons under international control, and hailed this as a victory against U.S. military threats.

But Russia has consistently blocked any Western attempt to sanction or restrain Damascus through UN resolutions.

Obama argues that Syria’s use of sarin violates a decades-old international taboo against chemical arms, and has said he is prepared to launch a punitive strike.

First, however, he has offered to wait to see if he can win approval from the U.S. Congress, and has embarked on a media blitz to sell intervention to the American public.

Briefing a congressional committee, Kerry alleged Syria has 1,000 metric tons of chemical weapons — including components for mustard and sarin gas.

“Yesterday, we challenged the regime to turn them over to the secure control of the international community so that they could be destroyed,” he told lawmakers.

Obama has said he is prepared to act alone or with a small coalition of allies, even if Russian opposition prevents a UN mandate.

But lawmakers remain wary of seeing U.S. forces dragged into a new Middle East conflict, and on Tuesday some were crafting a measure that would delay approval of the strikes.

“Basically, the AUMF (authorization for use of military force) would be conditional and triggered only if the Russian plan fails,” a Senate aide told AFP.

In Damascus, civilians in Assad-controlled areas expressed relief that the US strike plan appeared to be receding, and the government welcomed the rival Russian initiative.

Syrian rebel leaders were outraged however, denouncing international “apathy” and arguing that delays while the U.S. Congress or the UN Security Council debates bolstered the regime.

The crisis flared when Assad’s forces launched a brutal crackdown on anti-regime protests in March 2011, and spiraled into a civil war that has killed more than 100,000 people.

AFP Photo/Chip Somodevilla