ST. PETERSBURG, Russia (AP) — President Barack Obama is heading into the lion’s den of Russia, confronting Syria’s key patron as well as foreign leaders skeptical of his call for an international military strike against Bashar Assad’s government.

Obama on Thursday began a two-day visit to St. Petersburg for the Group of 20 economic summit, putting him in the same country as Edward Snowden for the first time since the American fugitive fled to Moscow earlier this year. Both Syria and Snowden have been sore points in an already strained U.S.-Russian relationship, fueling the notion that Obama and Russian President Vladimir Putin just can’t get along.

The White House went out of its way to say Obama, who arrived Thursday after a quick flight from Stockholm, would not meet one-on-one with the Russian leader while in St. Petersburg. But officials predicted the two would still have a chance to interact when they cross paths at various meetings.

Still struggling to persuade dubious lawmakers at home on Syria, Obama in Russia will seek to win over world leaders reluctant to get drawn in to yet another U.S.-led sortie in a Mideast nation. Although Syria wasn’t formally on the agenda for the economy-focused summit, U.S. officials were resigned to the fact that the bloody civil war there surely would overwhelm any talks about global economics.

Shortly after his arrival in St. Petersburg, Obama met on the summit’s sidelines with Japanese Prime Minister Shinzo Abe. He planned similar meetings Friday with the leaders of France and China.

In an ironic twist for Obama, the nation hosting the summit is also the nation most forcefully obstructing Obama’s path to an international consensus. Russia has provided critical military and financial backing for Assad and has leveraged its veto power in the U.N. Security Council to keep a resolution condemning Syria from getting off the ground. At the same time, Obama has had little success enticing individual nations to join the effort.

At the top of his meeting with Abe, Obama said the two leaders would discuss Syria as well as their continued concerns about the nuclearization of the Korean Peninsula and the importance of North Korea abiding by international law. But he said their primary focus would be on the economy and how they can improve jobs and growth.

Complicating Obama’s efforts to present a united front on Syria is the raging debate in Congress over whether to approve a strike — a debate Obama invited when he abruptly decided Saturday to seek congressional approval amid deep concerns from both parties. Some lawmakers view Obama as trying to preserve his own credibility after issuing an ultimatum to Assad last year against using chemical weapons.

"My credibility is not on the line. The international community’s credibility is on the line," Obama said Wednesday at news conference in Stockholm.

While insisting Obama has yet to prove his case, Putin appeared to temper his rhetoric slightly in a pre-summit interview with The Associated Press, saying he wouldn’t rule out backing a U.N. resolution if it can be proved Assad gassed his own people with chemical weapons, as the U.S. has alleged.

He also played down any personal tensions with Obama while acknowledging the parsing of the body language that’s become a geopolitical parlor game every time the two leaders meet.

"President Obama hasn’t been elected by the American people in order to be pleasant to Russia," Putin said. "And your humble servant hasn’t been elected by the people of Russia to be pleasant to someone either."

Ben Rhodes, Obama’s deputy national security adviser, cast doubt on Putin’s softer tone, adding the U.S. was "highly skeptical" that Russia would act differently if the Security Council were to take up the Syria issue again. And Putin, speaking to his human rights council a day after the AP interview, minced no words about U.S. Secretary of State John Kerry, whom he accused of whitewashing ties between al-Qaida and some rebel groups in Syria.

"He is lying and he knows that he is lying. This is sad," Putin said.

Such comments reflected a serious deterioration of relations since the summer of 2009 when Obama, on his last visit to Russia, trumpeted a "reset" in relations between the former Cold War foes.

"This will not be easy," Obama said in Moscow. "It’s hard to change habits that have been ingrained in our governments and our bureaucracies for decades."

Indeed, it hasn’t been easy. The crisis in Syria joins a long list of contentious issues that have made cooperation between the countries a trying endeavor, even though Obama points to successes early in his presidency on nuclear stockpile reduction and trading regulations. More recently, the two have butted heads over missile defense, human rights and other issues.

Obama will call attention to one such area of disagreement — gay rights — when he meets Friday in St. Petersburg with lesbian, gay, bisexual and transgender activists.

The lead-up to Obama’s arrival at the G-20 was notable not for what he did, but for what he didn’t do: visit Moscow. The president had been set to go to the Russian capital for a face-to-face with Putin but dramatically abandoned those plans last month after Russia granted asylum to Snowden, flouting Obama’s requests that he be returned to the U.S. The former National Security Agency systems analyst faces espionage charges after absconding with a trove of documents detailing secret U.S. surveillance programs and leaking them to the media.

"However people in the West look at Snowden, the Russians saw him as a defector," said Steven Pifer, a former U.S. ambassador and Russia expert at the Brookings Institution in Washington. "And the rules of the game are, you don’t return defectors."

After calling off the meeting with Putin, Obama decided instead to visit Sweden, where he met Wednesday with Prime Minister Fredrik Reinfeldt and other Nordic leaders. He wrapped up his visit Thursday with a meeting with King Carl XVI Gustaf at Sweden’s Royal Palace.

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AP White House Correspondent Julie Pace in St. Petersburg contributed to this report.

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Follow Josh Lederman on Twitter at http://twitter.com/joshledermanAP