Syria says it has accepted Russia's proposal to place its chemical weapons under international control for subsequent dismantling.
Syrian Foreign Minister Walid al-Moallem said last night that his government had quickly "agreed to the Russian initiative".
Al-Moallem said that Syria did so to "uproot US aggression".
Meanwhile, Russia's Foreign Minister Sergey Lavrov said that Russia is now working with Syria to prepare a detailed plan of action.
But Russia's proposal would be troublesome to enact, given it would require time and total co-operation from a secretive regime fighting for survival. Experts say the idea - sparked by United States Secretary of State John Kerry and developed by Lavrov - in which Syria's arsenal would be destroyed under supervision, ventures into uncharted territory. Previous arms control efforts have been carried out after - not during - a conflict.
Last night, Human Rights Watch added to the debate with a 22-page report arguing that Syrian government forces were most likely to blame for the chemical weapons attack last month in Damascus that left hundreds dead.
HRW issued its findings after analysing witness accounts of the rocket attacks in Ghouta on August 21, information on the likely source of the attacks, physical debris from weapons used, and the victims' symptoms.
The rights group said the type of rockets and launchers used in the attack were known to "be only in the possession of and used by" the Syrian armed forces.
HRW said the nerve agent sarin was probably used. It also said two kinds of rockets appeared to have been used - a 330mm rocket with a warhead designed to carry a large payload of liquid chemical agent, and a smaller 140mm rocket capable of carrying a warhead packed with 2.2kg of sarin.
With more than 1000 tonnes of chemical agents and precursor chemicals, the Syrian regime has one of the world's most significant stockpiles, according to a French intelligence report. But the process of removing such arms from President Bashar al-Assad's reach while rebel fighters continue to push for the fall of his Government would present major difficulties even if such an accord was reached.
"It's hard for me to imagine how that would happen in the middle of a civil war," said Daryl Kimball, executive director of the Washington-based Arms Control Association. "Because this is a very difficult engineering task. It requires facilities to be built to destroy the weapons."
Such an undertaking would require a long-term international presence to track the process. "It's not something you want to do with the threat of mortar shells hitting the area."
Kerry had suggested, in what appeared to be an off-the-cuff remark, that Syria could stop threatened US military strikes by placing its chemical weapons stockpile under international control. Within hours, as he was flying back to Washington from London, Russia had embraced the idea and the Syrian regime had also seemingly come on board. US President Barack Obama said it could be a "significant breakthrough".
Political tensions are high in Washington with Obama due to deliver an address today on the crisis and Congress beginning to debate a resolution calling for approval of US military strikes which appears unlikely to pass both Houses.
In the slow-moving world of Destroying
diplomacy, where every remark is carefully calibrated and deliberated, it's rare to see ideas spread like wildfire. It remained unclear whether this was just another misstep by the gaffe-prone Secretary of State, or a carefully choreographed plant, providing Obama with a possible exit strategy.
Obama himself added to the mystery by saying he had discussed the issue with Russian President Vladimir Putin last week. Obama told NBC that he believed "a credible threat of a military strike from the United States ... has given them pause".
The Russian proposal implies that Syria would have to sign the international Chemical Weapons Convention, forcing it to divulge every detail of its arsenal - a radical move for a regime preoccupied with buffeting its foes, both foreign and domestic.
Former UN weapons inspector David Kay, who oversaw the search for weapons of mass destruction in Iraq that were never found, has said that any effort to secure chemical weapons sites in Syria would require elaborate, constant security to "ensure that others are not entering".
Even in peaceful settings, destroying a chemical stockpile under international law is a complicated undertaking that takes years and billions of dollars, with international inspectors on hand at every step.
Under the international convention, the US has spent nearly US$35 billion to incinerate 90 per cent of its stockpile over more than two decades. Special destruction chambers had to be built at chemical weapons depots across the country with bombs, rockets and artillery shells destroyed one by one.
There are essentially two ways to get rid of chemical weapons: burning them in an incinerator, which has been the primary method in the US; or neutralising them with other chemicals, which has been the approach in Russia and - most recently - Libya, experts said.
Neutralising lethal agents drastically reduces their toxicity to a level equivalent to typical industrial waste, according to Michael Luhan, spokesman for the OPCW.