President Barack Obama is pressing fellow world leaders to support a US-led strike on Syria, but has run into opposition from Russia, China and even the European Union - which condemned the deadly recent chemical weapons attack in Bashar Assad's country but declared it too soon for military action.
"The use of chemical weapons in Syria is not only a tragedy but also a violation of international law that must be addressed," Obama insisted during a meeting with Japanese Prime Minister Shinzo Abe on the sidelines of the Group of 20 economic summit, where he mostly made his case behind the scenes.
China's G-20 delegation spokesman, Qin Gang, was among those who countered, saying: "War isn't the fundamental way to solve problems in Syria."
Obama's public and private diplomatic wrangling partly was intended to ratchet up pressure on lawmakers back in Washington as they debate authorising military action. The Senate Foreign Relations Committee passed a use-of-force resolution this week, but the measure's prospects in the full Senate and the House of Representatives are uncertain.
The prospect of military action against Syria overshadowed the global growth agenda at the two-day G-20 summit, which opened Thursday in this historic Russian city on the Baltic Sea. Leaders did, however, hold a lengthy discussion about the crisis during a four-hour dinner hosted by Russian President Vladimir Putin, one of Syria's strongest backers.
The dinner at St. Petersburg's Peterhof Palace stretched into the early hours of Friday and ended with an elaborate fireworks and laser light display.
White House advisers said Obama was seeking "political and diplomatic" support from his international counterparts, not necessarily military cooperation. And Ben Rhodes, Obama's deputy national security adviser, said the type of action the U.S. is contemplating "does not come with significant requirements of international participation."
While Obama has long called for the ouster of Assad, a deadly chemical weapons attack near Damascus two weeks ago pushed the U.S. to the brink of military action for the first time during Syria's civil war. The U.S. position on Syria has increased tensions with Putin, one of Assad's most important economic and military backers. Putin has blocked efforts at the United Nations to take action and has questioned intelligence reports American officials say link the chemical weapon deployment to the Syrian leader.
British Prime Minister David Cameron said Thursday (local time) that the United Kingdom had fresh evidence that was being examined at British laboratories.
Ahead of the US president's arrival in St. Petersburg, Putin told The Associated Press in an interview that it was "completely ridiculous" to assert that Assad was behind the use of deadly gases against Syrian citizens. The Kremlin also announced it was boosting its naval presence in the Mediterranean, where the US has five destroyers on standby for a military strike.
In keeping with the economic theme of the meeting, Chinese officials said military action would have a negative impact on the global economy, particularly oil prices.
The European Union also was skeptical about the effectiveness of military action. EU President Herman Van Rompuy told reporters in St. Petersburg that the August chemical weapons attack "was a blatant violation of international law and a crime against humanity," but he said a political, not military, solution was needed in Syria.
"While respecting the recent calls for action, we underscore at the same time the need to move forward with addressing the Syrian crisis through the UN process," Van Rompuy said.
The US, too, backs a political resolution in Syria, but has largely given up on efforts at the UN, where Russia has blocked Security Council efforts to punish Assad. Rhodes said Thursday that the Obama administration was "highly skeptical" that Russia would take a different posture if the US sought new resolutions at the Security Council.
At the UN on Thursday, US Ambassador Samantha Power said "Russia continues to hold the Council hostage and shirks its international responsibilities." She blamed the structure of the Security Council, which lets five major nations hold veto power - Russia, the United States, China, France and Britain.
In Syria itself, Assad's troops battled al Qaeda-linked rebels for a second day over the government-held Christian village of Maaloula. Rami Abdul-Rahman, the director of the Britain-based Observatory for Human Rights, said the fighters included members of the of al Qaeda affiliated Jabhat al-Nusra group.
For much of last week, it appeared Obama was ready to launch a strike against Assad's government without authorisation from either the UN or the US Congress. But he made an abrupt reversal on Saturday, announcing he would hold off on a military response and ask Congress for a vote in support. The White House has refused to say whether Obama would go forward with a strike if lawmakers vote against using force.
With one eye on Washington, Obama on Thursday lobbied lawmakers from afar, and he canceled a planned trip to California for next week to stay in Washington and make his case as votes near. Back home, his administration continued its full-scale sales job with another round of closed-door meetings for lawmakers about intelligence on Syria.
Senator Dianne Feinstein, chairwoman of the Senate Intelligence Committee, said officials showed a DVD on chemical weapons with "what pinpointed eyes mean, what the convulsions mean" when nerve agents affect people. She said all senators would receive a copy.
"It's horrendous," Feinstein said.
The administration has focused on influencing lawmakers who will vote, but opinion polls show little desire by the general public for military intervention in Syria.
"It weighs on me," Feinstein said of the lack of popular support. "There's no question: What's coming in is overwhelmingly negative."
An AP survey of senators found 34 supporting or leaning toward military action, 26 opposed or leaning against, and 40 undecided.
Among the undecided senators is Ron Wyden, a Democrat from Oregon.
"What the effects of a military strike would be are not clear," Wyden said.
While intelligence information on the recent chemical weapons attack has been provided to members of Congress, the public hasn't had the same access - a point Feinstein recognised, saying: "But you see, then they don't know what I know. They haven't heard what I've heard."
The Senate resolution authorises the "limited and specified use" of the U.S. armed forces against Syria, restricts military action to 90 days and bars American ground troops from combat.
The measure is expected to reach the Senate floor next week. The timetable is more uncertain in the Republican-led House, where the resolution is expected to face greater opposition. House Speaker John Boehner and House Majority Leader Eric Cantor, both Republicans, have backed military action in Syria, but there's no guarantee they'll be able to sway enough other members of their party.
Despite widespread condemnation of the chemical weapons attack from allies, there are few countries likely to join the US in undertaking military action if Obama moves forward with a strike. France has been the most favourable, though French officials said they were awaiting the outcome of the votes in Washington and would not proceed alone.
Obama and French President Francois Hollande were to hold a meeting on the sidelines of the summit Friday.