Geneva - Washington and Moscow said on Friday they hoped talks on dismantling Syria's chemical arsenal would open the door to wider peace efforts, as they held a second day of high-stakes meetings.
As the two met in Geneva, US Secretary of State John Kerry said he and Russian counterpart Sergei Lavrov would meet again later this month - probably around 28 September - to try to set a date for a long-delayed peace conference.
He said Washington and Moscow were "working hard to find common ground" to implement peace talks in Geneva that would bring together Syrian President Bashar Assad's regime and the opposition to negotiate a political solution to the conflict.
Much of the way forward "will obviously depend on the capacity to have success here in the next day, hours, days, on the subject of the chemical weapons," Kerry told reporters after meeting with Lavrov and the United Nations-Arab League envoy to Syria, Lakhdar Brahimi.
Lavrov said he also hoped a "basically abandoned" peace plan first agreed in Geneva in June last year would be revived.
"We agreed to meet in New York in the margins of the (UN) General Assembly and see where we are, and what the Syrian parties think about it and do about it," Lavrov said.
Washington and Moscow are hammering out the details of dismantling Assad's chemical arsenal under a Russian plan that emerged this week - kickstarting long-stalled diplomatic efforts on Syria.
The last-minute Russian initiative caused US President Barack Obama to back away from planned military strikes in response to a chemical attack that allegedly killed hundreds of people last month.
Assad confirmed for the first time Thursday that Syria planned to relinquish its chemical arms, and Russian President Vladimir Putin urged the global community to take him seriously.
"This confirms the serious intentions of our partners to go along this path," Putin said at a security summit in Kyrgyzstan, adding that diplomatic efforts had reduced "an immediate threat of a military operation".
A statement from the summit of the Shanghai Co-operation Organisation (SCO) said the group supported the Russian initiative and opposed any actions that could lead to a "further militarisation" of the situation in Syria.
The SCO, whose members include Russia, China and several Central Asian states, is a regional security group sometimes seen as an eastern counterweight to Nato.
Iranian President Hassan Rowhani, whose country has observer status at the SCO, said Tehran also fully backed the Russian initiative.
"We believe that the situation in Syria should be decided politically and without foreign military intervention. All influential and interested sides should lead a constructive dialogue in that direction," he said.
Syria on Thursday filed documents at the United Nations seeking to join the international convention banning chemical weapons and said it now considers itself a full member.
While UN leader Ban Ki-moon welcomed the application, the United Nations would not immediately confirm it had been accepted.
And Washington warned the regime that further steps were needed before military action would be off the table, with Kerry saying words "are simply not enough".
Syria's opposition National Coalition also said it was "deeply sceptical" of the government's move and urged a tough UN resolution to enforce the measure.
"It is vital the threat of force stays on the table. For a [UN Security Council] resolution to be anything other than a get-out-of-jail-free card for the regime, it must be enforceable under Chapter 7," allowing military action, it said in a statement.
Fuelling concerns about Assad's sincerity, reports emerged Friday that a secret Syrian military unit was scattering the chemical weapons stockpile around the country.
1 000 tons
The unit was given responsibility to shift the arsenal of poison gases and munitions to different locations across Syria, the Wall Street Journal reported, citing US and Middle Eastern officials.
Kerry and Lavrov are being joined in Geneva by large teams of weapons experts, with specialists warning that any programme to dismantle Syria's reported 1 000 tons of chemical weapons would be extremely complicated.
Russia has not revealed many details of its plan, but Russian media reports say it calls for a four-step process for the weapons handover.
Reports say the plan calls for Damascus to join the Organisation for the Prohibition of Chemical Weapons (OPCW), declare the locations of its chemical arms, allow OPCW inspectors access and finally arrange for destruction of the arsenal.
The United States and France, Washington's main backer for military strikes, have warned they will not allow the chemical weapons plan to become a delaying tactic in Syria's conflict, which has claimed more than 110 000 lives since March 2011.
Russia, which backed by China has blocked any attempt to sanction Syria through the UN, vigorously opposes military strikes.
Washington alleges that about 1 400 people died in the chemical attack on 21 August in the Damascus suburbs.
UN inspectors are due to release the results of an investigation into the attack early next week, and a report in the Times of London Friday said they would blame the Assad regime for the attack.