SYRIAN President Bashar al-Assad formally embraced a Russian plan for his regime to relinquish its chemical weapons arsenal but appeared almost in the same breath to set conditions, notably that the US should first lift the threat of military strikes and cease arming Syrian rebels.
The caveats introduced by Mr Assad in an interview with a Russian television station threatened to unsteady the delicate diplomatic process just as it was getting into high gear with the opening last night of joint talks in Geneva between the US Secretary of State, John Kerry, and his Russian counterpart, Sergei Lavrov.
While the United Nations said it had received an official application from Syria to join the Chemical Weapons Convention, Mr Assad also suggested he would begin submitting details of its existing stockpile to international monitors one month after joining, a far longer timetable than that envisaged by Washington.
At the outset of the talks in Geneva, Mr Kerry instantly rejected Mr Assad's 30-day window and said words from the regime are "not enough". Standing beside Mr Lavrov, Mr Kerry noted firmly that possible military strikes remained on the table in case the diplomatic track fails and that the transfer of the weapons must be "verifiable and timely". 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 the 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".
Mr Assad said today 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, Mr 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 Mr Assad's feet to the fire.
Mr 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.
The 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".
Mr Obama gave the green light to supply a limited array of arms to the rebels in the early summer but Syrian opposition groups still insisted today 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 Mr Kerry and Mr 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 Mr Assad.
On a parallel track at the United Nations, meanwhile, France was preparing last night 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 21 August 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 after Monday when the UN inspectors who travelled to Syria in the wake of 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.
When Presidents talk Syria: Who's winning the war of words?
Once their nations squared up across the Iron Curtain with threats of mass destruction. This week, Barack Obama and Vladimir Putin have been trading rhetoric. On Tuesday, the US president addressed his nation about his plans for military strikes against the Assad regime. Today, his Russian counterpart presented a contrasting view in the New York Times. Who is winning the arguments so far? Make up your mind with the help of these extracts...
What would an American strike on Syria achieve?
Obama: "With modest effort and risk, we can stop children from being gassed to death and thereby make our own children safer over the long run…"
Putin: "The potential strike… will result in more innocent victims and escalation, potentially spreading the conflict far beyond Syria's borders... It could throw the entire system of international law and order out of balance."
Was poison gas used, and if so by whom?
Obama: "We know the Assad regime was responsible... Assad's chemical weapons personnel prepared for an attack... They distributed gas masks to their troops. Then they fired rockets into 11 neighbourhoods the regime has been trying to clear of opposition forces."
Putin: "No one doubts that poison gas was used in Syria. But there is every reason to believe it was used not by the Syrian army, but by opposition forces, to provoke intervention by their powerful foreign patrons, who would be siding with the fundamentalists."
America's moral leadership of the world
Obama: "Our ideals and principles, as well as our national security, are at stake in Syria, along with our leadership of a world where we seek to ensure that the worst weapons will never be used... I believe we should act. That's what makes America different."
Putin: "Millions around the world increasingly see America not as a model of democracy, but as relying solely on brute force, cobbling coalitions together under the slogan: "You're either with us or against us."
The likely consequences of military action
Obama: "The United States military doesn't do pinpricks. Even a limited strike will send a message to Assad that no other nation can deliver. A targeted strike can make Assad or any other dictator think twice before using chemical weapons. Other questions involve the dangers of retaliation. We don't dismiss any threats, but the Assad regime does not have the ability to seriously threaten our military."
Putin: "Civilian casualties are inevitable, including the elderly and children, whom the strikes are meant to protect. The world reacts by asking: if you cannot count on international law, then you must find other ways to ensure your security. Thus a growing number of countries seek to acquire weapons of mass destruction… We must stop using the language of force and return to the path of civilised diplomatic and political settlement."
On the consequences of not taking military action
Obama: If we fail to act, the Assad regime will see no reason to stop using chemical weapons... Other tyrants will have no reason to think twice about acquiring poison gases and using them... Our troops would again face the prospect of chemical warfare on the battlefield and it could be easier for terrorist organisations to obtain these weapons..."
Putin: "If we can avoid force against Syria, this will improve the atmosphere in international affairs and strengthen mutual trust. It will be our shared success and open the door to co-operation on other critical issues."
On the doctrine of American exceptionalism
Obama: "For nearly seven decades the United States has been the anchor of global security. This has meant doing more than forging international agreements. It has meant enforcing them. The burdens of leadership are often heavy, but the world is a better place because we have borne them."
Putin: "It is extremely dangerous to encourage people to see themselves as exceptional... There are big countries and small countries, rich and poor, those with long democratic traditions and those still finding their way to democracy. Their policies differ, too. We are all different, but when we ask for the Lord's blessings, we must not forget that God created us equal."