He said: "This is not a game; it has to be real."
US officials made clear that the talks represented a first opportunity to assess the seriousness of the Russian proposal and ensure that it is not an elaborate stalling strategy conceived by Moscow to protect Syria from US attack. The talks are expected to last two days and possibly more. For now the US Administration is evincing cautious optimism.
"I am hopeful that the discussions that Secretary Kerry has with Foreign Minister Lavrov as well as some of the other players in this can yield a concrete result," President Barack Obama said at the White House. Darkening the mood in Washington, however, was the publication in the New York Times of an opinion piece by Russian President Vladimir Putin in which he stressed the importance of solving the Syria crisis without violence but blamed the rebels for the gas attacks and chastised the US for its self-described "exceptionalism".
It drew anger on Capitol Hill, with the House Speaker John Boehner saying he was insulted.
Assad said yesterday that he had been persuaded to accept controls of his weapons by Russia alone.
"Threats made by the US did not influence our decision to permit monitoring of our chemical weapons by the international community," he said.
By contrast, Obama has publicly stated that it was the threat of strikes that brought Syria to the table and intends to maintain the threat to keep Assad's feet to the fire.
Assad's reference to arms deliveries coincided with official word from the US side for the first time that the CIA is indeed now supplying Syrian rebels with armaments and has been doing so for the past month.
National Security Council spokeswoman Bernadette Meehan said the US would not "detail every single type of support that we are providing to the opposition or discuss timelines for delivery, but it's important to note that both the political and the military opposition are and will be receiving this assistance".
Obama gave the green light to supply a limited array of arms to the rebels in the early northern summer but Syrian opposition groups still insisted yesterday that none had yet arrived. The CIA is believed to be sending small arms to the rebels and, through a third party, some anti-tank weaponry.
Teams of disarmament experts accompanied Kerry and Lavrov to the talks in a Geneva hotel.
Both sides said the agenda would be largely technical, exploring the extremely challenging practicalities of actually identifying, gathering up and eventually disabling the Syrian arsenal in the midst of civil conflict, and would not be about negotiating the broader terms of the plan, including deadlines for compliance and the seemingly slow timetable favoured by Assad.
On a parallel track at the United Nations, meanwhile, France was preparing yesterday to circulate the text of a draft resolution that it, the US and Britain will jointly table at the UN Security Council.
First drafts drew Russian resistance, however, because it explicitly blamed the Syrian regime for the gas attacks of August 21 and introduced wording that would allow for the possible use of force in the event Syria fails to comply.
What promises to be an extremely difficult debate in the Security Council is not likely to begin, however, until next week when the UN inspectors who travelled to Syria after the gas attacks are expected to submit a preliminary report.
France's Foreign Minister, Laurent Fabius, said he expected it to confirm "a chemical massacre" and that it would include at least "indications" of the attack's origin.
- Independent
