WASHINGTON -- President Barack Obama this week plans to urge reluctant world leaders to support a U.S.-led military strike against Syria as he attends a global summit in Russia and makes a stop in Sweden. His three-day overseas trip comes as his administration seeks authorization from Congress.

Top lawmakers signalled support Tuesday after meeting with Obama, while France said it will wait for Congress' decision before any military action of its own.

Obama's presence at the Group of 20 gathering in Russia is bound to bring questions about Syria, recently leaked U.S. surveillance programs and especially his tense relationship with Russian President Vladimir Putin, an ally of Syrian President Bashar Assad.

"It's been like watching a slow-moving train wreck for nearly two years," Andrew Kuchins, a Russia expert at the Center for Strategic and International Studies, said of the Obama-Putin relationship. "Mr. Putin and Mr. Obama don't like each other at all."

That's not Obama's only headache.

His surprise announcement over the weekend that he would seek congressional authorization for a military strike against Syria, instead of going ahead with a strike as many expected, may have caused doubts among world leaders about his willingness to follow up on his threats to rogue nations.

His administration argues that the strike is needed in response to what it says was a deadly chemical weapons attack last month.

Before his White House meeting Tuesday with top lawmakers, Obama said he is confident he will be able to work with Congress to pass a resolution authorizing the strike on Syria. Obama said congressional authorization must send a clear message to Assad and hamper his ability to use chemical weapons.

After the meeting, the top Republican in Congress, House Speaker John Boehner, said he would support Obama's call for action against Syria and said his party colleagues should, too.

Votes in the House and the Senate are expected next week, just after Obama ends his overseas trip. He leaves for Sweden later Tuesday.

Syria isn't officially on the agenda at the economy-focused G-20 summit. But world leaders are expected to ask Obama whether he plans to proceed with a military strike if Congress doesn't support it. It's a question Obama's aides have refused to answer.

Obama spoke about Syria by telephone Monday night with Japanese Prime Minister Shinzo Abe, the White House said Tuesday. A White House statement said Obama and Abe pledged to consult on a possible international response.

Obama is to arrive in Stockholm on Wednesday morning after an overnight flight from Washington.

The White House hastily added the Sweden visit to his schedule after he cancelled plans to meet one-on-one with Putin in Moscow ahead of the G-20. That came in response to the Kremlin granting temporary asylum to National Security Agency leaker Edward Snowden, defying Obama's requests to send the former NSA systems analyst back to the U.S. to face espionage charges.

Snowden's leaks to American and foreign news organizations about secret government spying programs have sparked outrage overseas, particularly in Europe. Obama is likely to face questions about the scope of the programs while overseas.

Tensions are also high over U.S. concerns on human rights and a new Russian law that targets "homosexual propaganda." Russian gay rights activists say they've been invited to meet with Obama while he is in St. Petersburg this week.

Even before the Snowden incident, relations between the U.S. and Russia were already troubled. Putin has appeared to enjoy blocking U.S. and Western European efforts to weaken Assad throughout Syria's 2 1/2-year civil war. Russia remains one of Syria's strongest military and economic backers.

Putin last week asked Obama to reconsider a military strike, saying he was appealing to Obama not as a world leader, but as a Nobel Peace laureate.

Administration officials insist the U.S. and Russia can still work productively together during the G-20.

The White House has ruled out a one-on-one meeting between Obama and Putin on the sidelines of the summit.

But Obama may sit down with counterparts from Britain and France. Britain's Parliament last week voted against endorsing military action in Syria, all but guaranteeing Britain won't play a direct role in any U.S.-led effort.

Obama's stop in Sweden on Wednesday will focus on issues such as climate change, security co-operation and trade. He will hold private meetings with Prime Minister Fredrik Reinfeldt and Swedish King Carl XVI Gustaf and will eat with Nordic leaders from Finland, Denmark, Iceland and Norway.