ST. PETERSBURG, Russia (AP) — President Barack Obama is using his last day in Europe to renew his quest for foreign support for a U.S. military strike in Syria. But three days after he left Washington, it’s unclear whether the global coalition the president has been seeking is any closer to becoming a reality.

China’s a firm no. The European Union is skeptical about whether any military action can be effective. Even Pope Francis weighed in, urging leaders gathered here to abandon what he called a "futile mission."

Still, Obama was undeterred. As the president pressed his case on the world stage, he was dispatching his U.N. ambassador, Samantha Power, to a Washington think tank to argue that the global community cannot afford the precedent of letting chemical weapons use go unpunished.

Illustrating the risks associated with a strike, however, the State Department on Friday ordered nonessential U.S. diplomats to leave Lebanon, a step under consideration since Obama said he was contemplating military action against the Syrian regime last week. The travel warning said it had instructed nonessential staffers to leave Beirut and urged private American citizens to depart Lebanon.

Yet even as Obama sought the global buy-in that could legitimize a potential strike, his aides were careful to temper expectations that the world community could speak with one voice. Obama’s deputy national security adviser, Ben Rhodes, said the president wasn’t asking his peers to pledge their own militaries to a U.S.-led strike, but simply to say they agree a military response is warranted.

"We don’t expect every country here to agree with that position," Rhodes said Friday at the Group of 20 economic summit, where Obama was huddling with foreign leaders.

Standing on Russian soil, Rhodes suggested the U.S. had given up hope that Russia — a stalwart Syria ally — could be coerced into changing its position. "We don’t expect to have Russian cooperation," he said.

A key status update was to come Friday when Obama, his diplomatic dexterity pushed to the max, will be quizzed by reporters in the waning hours of the summit.

A jobs-and-growth agenda awaiting world leaders gathering at the ornate Constantine Palace quickly gave way to intense posturing over Syria — at least on the surface. The leaders served up Syria as dinner conversation Thursday at the suggestion of the summit’s host, President Vladimir Putin. The Russian leader has steadfastly backed Syrian President Bashar Assad and disputes claims that Assad’s regime was behind chemical attacks that the U.S. says killed more than 1,400 Syrians. Other estimates are lower.

Syria dominated the nearly three-hour meal, with leaders condemning the use of chemical weapons but reaching no consensus about the proper response, said a French official in St. Petersburg. Many leaders at the dinner remained in doubt about whether Assad’s regime was behind the attack, said the official, who was not authorized to be publicly named according to presidential policy.

So too was the Syrian crisis a prevailing theme in Obama’s individual meetings with world leaders on the sidelines of the summit in this Russian port city.

The White House said Obama conferred on Syria Thursday evening with Turkish Prime Minister Recep Tayyip Erdogan, a strong supporter of airstrikes against the nation on its southern border. Syria also came up on Friday as Obama met with Chinese President Xi Jinping, whose government has warned vigorously against the use of force.

Before his scheduled return to Washington late Friday, Obama was to meet with French President Francois Hollande, his strongest ally on Syria and a vocal advocate for a military intervention. He also planned to meet with Russian lesbian, gay, bisexual and transgender activists, calling attention to another area of disagreement with Moscow.

A fleeting interaction between Obama and Putin became the high-drama moment of the summit, underscoring the labored state of relations between the two leaders. The eyes of the world watching, the Russian and the American were all smiles Thursday as they made small talk in front of news cameras for a few seconds as Obama arrived at the summit.

But the welcoming handshake may have been where the pleasantries ended. In other venues, the two nations were repeatedly bumping heads.

Russia’s foreign ministry, in a statement Friday, said a U.S.-led strike would mark "a new dangerous turn" in the crisis, risking the release of chemical weapons or their possession by terrorists. And the head of the foreign affairs panel in Russia’s lower house of parliament, Alexei Pushkov, blasted Obama on Twitter as having "completely transformed into a president of war."

Meanwhile, the Kremlin said Russia was boosting its naval presence in the Mediterranean Sea, moving in warships into the area and stoking fears about a larger international conflict if the United States orders airstrikes.

Even at home, there was far from a consensus that an American strike on Syria was the best course of action. Awaiting Obama upon his return was an equally fractious debate in Congress over whether to authorize the limited military action he was proposing.

Pulling out all the stops, Obama was working the phones from Europe and appealing for support from leery lawmakers, Democratic and Republican alike. And he called off a planned trip to California next week, opting to stay in Washington to keep up the pressure on Congress to say yes.

As top national security officials continued to brief Congress on the accusation against Assad and the proposed response, a measure authorizing Obama to act was advancing tenuously through the Senate, winning approval from a foreign relations panel Wednesday and heading to the Senate floor. The measure’s prospects were dicier in the Republican-controlled House.

In an unusual turn of events, Senate Majority Leader Harry Reid and House Speaker John Boehner both said that a delegation of Russian lawmakers had sought to meet with them to discuss Syria. Both leaders, who are supporting Obama’s call for a strike, turned down that invitation, aides said.

"I don’t know that the Russians have anything to add to the debate in the United States, given that we know where Russia stands," said Rhodes, the Obama aide.

The fierce domestic debate over a Syria strike offered a prelude to grueling days ahead as Obama and Congress brace for major clashes over the nation’s finances, immigration and other pressing issues. When lawmakers return next week from their annual summer recess, Syria will compete with critical, looming deadlines to raise the nation’s borrowing limit and approve spending to avoid a government shutdown.

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Associated Press writer Angela Charlton contributed to this report.

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