Washington - Russia issued a stark warning on Thursday that unilateral US military action could destroy world order, as the rival great powers discussed a plan to remove Syria's chemical weapons.
In a bid to appeal directly to US voters and policy-makers over the head of President Barack Obama, Kremlin leader President Vladimir Putin penned a commentary in the New York Times.
His article appeared at the same time as US Secretary of State John Kerry took off for Geneva, where he was to work with his Russian counterpart Sergei Lavrov on a plan to neutralise Syria's chemical arsenal.
Putin welcomed Washington's willingness to engage with the Moscow initiative, but he rebuked Obama for his previous threat to launch US military strikes to punish Bashar Assad's regime.
He warned that carrying out such a move without the approval of the United Nations Security Council, where Moscow wields a veto, would destroy the credibility of the world body.
"No-one wants the United Nations to suffer the fate of the League of Nations, which collapsed because it lacked real leverage," he said, referring to the United Nations' failed inter-war predecessor.
"A strike would increase violence and unleash a new wave of terrorism," Putin wrote, in a piece that emphasized that many of the rebels ranged against Assad have ties to al-Qaeda.
"It could undermine multilateral efforts to resolve the Iranian nuclear problem and the Israeli-Palestinian conflict and further destabilise the Middle East and North Africa," he continued.
"It could throw the entire system of international law and order out of balance," he said.
Syria is a traditional ally of Russia, and Moscow has blocked any attempt to sanction his regime through the United Nations during the two-and-a-half year civil war that grips his country.
Last month, when hundreds of civilians were killed in a night of chemical weapons strikes in the suburbs of Damascus, the United States and France threatened to take action.
Despite a US intelligence report that tied the strike to Assad's regime and alleged that 1 400 people died, Obama struggled to win domestic support for unilateral action.
Then on Monday, Russia announced a plan for Syria to surrender its banned weapons to international control for destruction. The Assad government said it would comply.
Despite deep scepticism about both Russia and Syria's sincerity, Obama agreed to examine the plan.
In an address to the American people on Tuesday he postponed, but did not withdraw, the threat of military action and ordered Kerry to meet Lavrov and work on the details.
"Judging by the statements of President Obama, the United States sees this as an alternative to military action," Putin wrote.
"I welcome the president's interest in continuing the dialogue with Russia on Syria. We must work together to keep this hope alive."
But, in a sign that Putin sees the crisis as an opportunity to reassert Russian influence two decades after the former Soviet Union lost the Cold War, he also levelled broader criticism at Washington.
Drawing on a passage in Obama's Tuesday night address that said the United States' has an "exceptional" role to play, Putin said it was wrong for any power to presume a unique leadership role.
"It is extremely dangerous to encourage people to see themselves as exceptional, whatever the motivation," he wrote.
"We are all different, but when we ask for blessings, we must not forget that God created us equal."
Earlier, envoys from the five veto-wielding permanent members of the Security Council - Britain, China, France, Russia and the United States - held inconclusive talks on Syria at the United Nations.
Rebel coalition distressed
Kerry, meanwhile, was en route for Geneva with a team of arms experts and senior officials to spend two to three days with Lavrov poring over Russia's proposal.
The most vocal advocate for Obama's call for strikes to punish Assad, Kerry alleged this week that Damascus has 1 000 metric tonnes of deadly chemical agents, including sulphur, mustard, sarin and VX.
While in Geneva, Kerry will also seek to revitalise political moves to call a peace conference to end Syria's civil war, in which more than 110 000 people have died since March 2011.
He will meet UN-Arab League envoy Lakhdar Brahimi to discuss UN-backed efforts to bring the Assad regime to the table with the opposition rebels.
The Syrian opposition has reacted with dismay to the Russian plan, warning that negotiations over chemical weapons will only deepen the chaos and misery in their country.
With the risk of an attack having receded, Assad - who celebrated his 48th birthday on Wednesday - was free to pursue his battle with a distressed rebel coalition.
The regime carried out an air strike on a field hospital in the province of Aleppo, killing at least 11 people, according to the Britain-based Syrian Observatory for Human Rights.
Rebel Sunni hardliners killed at least 20 civilians in the central province of Homs, with fighters from the Qaeda-linked al-Nusra Front and other groups attacking Alawite villages, the Observatory said.
Assad, a secular leader who has largely protected the rights of minorities, belongs to the heterodox Alawite sect, which Sunni hardliners consider un-Islamic.
Sunni Arab monarchies Qatar and Saudi Arabia have funded the rebels, while Shi’ite theocracy Iran has staunchly backed Assad.