A Senate panel has voted to give U.S. President Barack Obama the authority to use military force against Syria in response to what the White House claims was a deadly chemical weapons attack perpetrated by the Syrian regime.

The resolution passed by a 10-7 vote, aided by support of three Republicans, including Senator John McCain.

Earlier, McCain, an outspoken advocate of intervention in Syria, had said he did not support the resolution, saying he wanted more than cruise missile strikes and other limited action. He had also sought a stronger response aimed at "reversing the momentum on the battlefield" and hastening the departure of Syrian President Bashar al-Assad.

Some minor changes to the resolution were made.

The resolution would permit Obama to order a limited military mission against Syria, as long as it doesn't exceed 90 days and involves no American troops on the ground for combat operations.

The Democratic chairman of the foreign relations committee, Senator Bob Menendez, and the panel's top Republican, Senator Bob Corker, crafted the resolution.

The vote marked the first time lawmakers have voted to authorize military action since the October 2002 votes giving then president George W. Bush the authority to invade Iraq.

The committee's vote was the first in a series, as the president's request makes its way through Senate and House committees before coming before the two chambers for a final vote.

The White House released a statement Wednesday afternoon commending the Senate for "moving swiftly" across party lines "on behalf of our national security."

"The military action authorized in the resolution would uphold America's national security interests by degrading Assad's chemical weapons capability and deterring the future use of these weapons, even as we pursue a broader strategy of strengthening the opposition to hasten a political transition in Syria," the statement said.

The Obama administration still needs to persuade a Republican-dominated House of Representatives that has opposed almost everything on Obama's agenda since the party seized the majority more than three years ago. The top opposition Republican in Congress, House Speaker John Boehner, has signalled key support, saying the U.S. has "enemies around the world that need to understand that we're not going to tolerate this type of behaviour."

On the other side of the debate, Republican Senator Jim Inhofe said he was not persuaded to support military action, saying the military has been "decimated" by budget cuts and "we're just not in a position to take on any major confrontation."

Intervention could 'make the tragedy worse'

Republican Senator Rand Paul said U.S. involvement could well "make the tragedy worse" in Syria, but he predicted that advocates of military intervention would win in the Senate.

"The only chance of stopping what I consider to be bad policy would be in the House," he said.

Obama, asked in Sweden about his own past comments drawing a "red line" against the use of chemical weapons, said it was a line that had first been clearly drawn by countries around the world and by Congress, in ratifying a treaty that bans the use of chemical weapons.

"That wasn't something I just kind of made up," he said. "I didn't pluck it out of thin air. There's a reason for it."

Obama said that if the world fails to act, it will send a message that despots and authoritarian regimes "can continue to act with impunity."

"The moral thing to do is not to stand by and do nothing," he declared at a news conference in Stockholm with Swedish Prime Minister Fredrik Reinfeldt.

Asked whether he would take action against Syria if he fails to get approval from Congress, the president said his request to lawmakers was not "an empty exercise." But he said that as commander-in-chief, "I always preserve the right and the responsibility to act on behalf of America's national security."

For its part, Canada is holding out little hope of reaching a compromise with Russia on the continuing violence and alleged use of chemical weapons in Syria, as Stephen Harper and fellow leaders began arriving Wednesday for the G20 summit.

Canadian Foreign Affairs Minister John Baird threw cold water on the prospect of a larger consensus on a response to the escalating situation in Syria.

"I think we hope that rational, sane people, freedom-loving people, people who abhor the use of these weapons, want to work collectively to ensure to the best of our ability that these weapons are not used again," Baird told reporters.

"[Russia] picked a lane in this battle years ago and I just don't foresee it changing. This is the great issue we're tackling, Russia's great intractability to work with others on this issue. In some respects that's the heart of the problem."

Kerry, Hagel make case at House committee

On Wednesday, Secretary of State John Kerry, Defence Secretary Chuck Hagel and the chairman of the Joint Chiefs of Staff, Gen. Martin Dempsey, were trying to make their case in a public hearing before the House Foreign Affairs Committee.

Kerry said that when chemical weapons were used in Syria last spring, Obama did not have a "compelling" enough case to push for a U.S. military response.

Kerry also said U.S. intelligence can prove Assad has used chemical weapons at least 11 times, and said North Korea and Iran were watching the U.S. closely.

"The world is wondering whether the United States of America is going to consent with silence," Kerry said.