President Bashar al-Assad confirmed for the first time that Syria plans to give up its chemical weapons as the United States urged him and his Russian allies to quickly make good on his promise.
But the long-time Syrian leader cast fresh doubt Thursday on how committed he is to a hastily-hatched plan to secure Syria's poison gas stocks by demanding that Washington first drop its threat of military action against his regime.
"When we see that the United States truly desires stability in our region and stops threatening and seeking to invade, as well as stops arms supplies to terrorists, then we can believe that we can follow through with the necessary processes," Assad told Russian television.
"Syria is handing over chemical weapons under international control because of Russia," he said. "US threats have not affected the decision."
Top US and Russian diplomats and weapons experts launched high-stakes talks late Thursday to pore over the details of the Russian plan, and were to huddle again in their Geneva hotel early Friday.
But US Secretary of State John Kerry warned Assad that "the words of the Syrian regime in our judgement are simply not enough".
Any deal to bring Syria's chemical weapons stockpile under international control "has to be credible. It has to be timely and implemented in a timely fashion," he said.
In a concrete move towards disarmament, Syria on Thursday filed documents at the United Nations seeking to join the international convention banning chemical weapons.
Damascus said it now considers itself a full member of the convention. While UN leader Ban Ki-moon welcomed the application, the United Nations would not immediately confirm it had been accepted.
Diplomats said it was possible there were missing elements and the application could be sent back to Assad.
Russian Foreign Minister Sergei Lavrov said he believed the "solution" to the issue of Syria's chemical weapons "makes unnecessary any strikes on Syria".
Pending the talks, US President Barack Obama has put on hold plans for limited military strikes against the Syrian regime to disable its chemical weapons capability, but US officials have repeatedly stressed that the option still remains on the table.
Lavrov, speaking through a translator, told Kerry that "I hope we will achieve all the successes".
But the top US diplomat quipped: "You want me to take your word for it? It's a little early for that".
The two men and their delegations met for about an hour before Lavrov and Kerry held a smaller dinner together. US officials described the talks as "comprehensive" and the atmosphere as "constructive."
Washington alleges that some 1,400 people died in a chemical attack on August 21 and was rallying support for a military response when the Russian proposal emerged.
UN inspectors will point the finger of blame at the Assad regime for the chemical weapons strike, the London Times reported Friday.
The inspectors' report, due to be published on Monday, will include a wealth of evidence that a chemical nerve agent was used in the attack, according to the paper's sources.
The United States and France, Washington's main backer of military strikes on Syria, have warned they will not allow the chemical weapons plan to become a delaying tactic in Syria's brutal war.
"All of this should, if everyone is aware of their responsibilities, allow for the end of chemical weapons in Syria and for us to find a political solution, but France is keeping up pressure," President Francois Hollande told reporters.
Revealing details of the Russian proposal, the daily Kommersant said Moscow had given Washington a four-step plan for the weapons handover.
Quoting a Russian diplomatic source, Kommersant said the plan would see Damascus 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.
Syria's opposition has denounced the plan, warning it will only lead to more deaths in a conflict that has already claimed more than 110,000 lives since March 2011.
Russian President Vladimir Putin, meanwhile, made an unusual personal appeal to the American people to reject military action.
"A strike would increase violence and unleash a new wave of terrorism," Putin wrote in an opinion piece in the New York Times. "It could throw the entire system of international law and order out of balance."
He warned any strikes without the approval of the United Nations Security Council, where Moscow wields a veto, would destroy the credibility of the world body.
Russia is a traditional ally of Assad, and Moscow, backed by China, has blocked any attempt to sanction his regime through the United Nations.
French Foreign Minister Laurent Fabius will visit China on Sunday to discuss the Syria plan, before travelling on to meet with Lavrov.
On Friday, Hollande will meet the foreign ministers of Saudi Arabia, Jordan and the United Arab Emirates, his office said.
Kerry also met Thursday with UN-Arab League envoy Lakhdar Brahimi to discuss UN-backed efforts to bring the Assad regime to the negotiating table with the rebels.
"We hope that once they have done what they have to do with the Russians on this chemical issue we will start talking again" about a Geneva peace conference, Brahimi said afterwards.