Ending weeks of diplomatic deadlock, the United States and Russia agreed on Thursday to a UN Security Council draft resolution that will demand Syria give up its chemical arms, but that does not threaten military force if Damascus fails to comply.

Samantha Power, the US ambassador to the United Nations, said a deal was struck with Russia "legally obligating" Syria to give up its chemical stockpile, and the measure went to the full Security Council in a closed-door meeting on Thursday night. UN diplomats said a vote could come within 24 hours.

"Just two weeks ago, tonight's outcome seemed utterly unimaginable," Power said, adding that two weeks ago, the Syrian government "had not even acknowledged the existence of its chemical weapons stockpiles".

"But tonight we have a shared draft resolution that was the outcome of intense diplomacy and negotiations over the past two weeks," she said.

US, Russian, French and British diplomats told reporters the vote could come as early as Friday evening, provided the Executive Council of the Organization for the Prohibition of Chemical Weapons in The Hague approves a plan for the destruction of Syria's poison gas arsenal beforehand.

"I know that some (foreign) ministers are extending their stay in New York in order to participate in that vote," Russian Ambassador Vitaly Churkin told reporters.

The agreement emerged from intense negotiations at the UN with Russia. The aim was to craft a measure to require destruction of Syria's chemical arsenal in line with a US-Russian deal reached earlier this month that averted US strikes on Syrian President Bashar al-Assad's forces.

Western powers on the Security Council backed away from many of their initial demands, diplomats say, in order to secure Russia's approval. Russian Foreign Minister Sergei Lavrov said an "understanding" had been hammered out, but did not elaborate.

A major sticking point had been Russia's opposition to writing the resolution under Chapter 7 of the UN charter, which covers the council's authority to enforce its decisions with measures such as sanctions or military force.

The compromise draft resolution, obtained by Reuters, makes the measure legally binding, but provides for no means of automatic enforcement, as the United States, the United Kingdom and France originally wanted.

Power said the resolution was groundbreaking because the council, which has been deadlocked for years on the Syrian civil war, formally endorsed for the first time a plan for a political transition in Syria that was agreed on at an international conference in Geneva in 2012.

'Breakthrough'

The only reference to enforcement in the draft is a threat that if Syria fails to comply with the resolution, the council would impose unspecified punitive measures under Chapter 7, which would require a second resolution that Russia could veto.

A US State Department official hailed the deal as a "breakthrough".

"The Russians have agreed to support a strong, binding and enforceable resolution that unites the pressure and focus of the international community on the Syrian government to ensure the elimination of Syria's chemical weapons," the official said.

Diplomats from the permanent Security Council members — China, Russia, the US, France and Britain — had been discussing the details of a resolution to back the US-Russian accord announced on Sept 14 in Geneva to eliminate Syria's chemical weapons.

Reuters—AFP