Kerry says Syria used sarin gas in deadly attack

WASHINGTON (AFP) - US Secretary of State John Kerry on Sunday spearheaded a drive to convince Congress to approve a military strike on Syria, saying Washington has proof the regime used sarin gas.

After President Barack Obama on Saturday asked US lawmakers to approve punitive military action against the Syrian regime, Kerry warned the world cannot turn a blind eye to chemical weapons use.

Hair and blood samples from the emergency workers who rushed to the scene of last month's attack in Damascus and given independently to the United States have shown signs of the powerful sarin nerve gas, Kerry told US television channels.

"In the last 24 hours, we have learned through samples that were provided to the United States and that have now been tested from first responders in East Damascus, (that) hair samples and blood samples have tested positive for signatures of sarin," Kerry told NBC's Meet the Press.

Kerry blitzed the Sunday morning television talk shows upping the momentum in the US administration's push to build the case for US military strikes against the regime of President Bashar al-Assad.

Obama, who next week will lay out America's case to world leaders at a G20 summit, took a huge political risk in committing the fate of US action to lawmakers -- moving to do so even after the British parliament voted against any military involvement in Syria.

The US commander-in-chief said he had decided the August 21 chemical weapons attack on a Damascus suburb that Washington says killed more than 1,400 people was so heinous -- and such a threat to long-term US security -- that he would respond with a limited military strike.

But he said he believed it was important to win support from Congress when it returns from its summer break on September 9.

His move disappointed the Syrian opposition, which pleaded with US lawmakers to "make the right choice."

"If the free world fails to respond to such an outrageous breach of international norms, dictators around the world will be encouraged in their efforts to follow the example set by Assad," the Syrian National Coalition said in a statement.

The Obama administration was Sunday briefing lawmakers again with Under Secretary of State Wendy Sherman and Under Secretary of Defense James Miller due to meet with them behind closed doors at the US Capitol.

The Senate Foreign Relations Committee will debate Syria on Tuesday and a Senate aide told AFP a vote on military force could come as early as Wednesday at 11:00 am (1500 GMT).

Obama will be relatively confident of winning a vote in the Democrat-controlled Senate.

But influential Republican Senator John McCain, who was due to hold White House talks with Obama on Monday, said he was not yet sure if he would support the move.

"We're in a bit of a dilemma here because I think Senator Lindsey Graham and I, and others, will be wanting a strategy, a plan, rather than just we're going to launch some cruise missiles and that's it," he told CBS television.

"But I also am aware of the failure of Congress to endorse this plan, the signal that it sends to the world, in a very dangerous world, where we've also lost enormous credibility."

He argued any US action needed "room for us to provide assistance to those who are struggling against overwhelming odds right now" to help end a brutal war which has claimed more than 100,000 lives since March 2010.

Republican Senator Rand Paul also delivered a sharp warning that Congress may reject military action amid fears the war could "escalate out of control."

"It's at least 50-50 whether the House will vote down involvement in the Syrian war," he told ABC.

"I think the Senate will rubber stamp what he wants, but I think the House will be a much closer vote, and there are a lot of questions we have to ask."

But Kerry insisted Congress would swing behind the president, warning "the stakes are too high here."

"I believe that as we go forward in the next days, the Congress will recognize that we can not allow Assad to be able to gas people with impunity," he told ABC's "This Week."

"If the United States is unwilling to lead a coalition of people who are prepared to stand up for the international norm with respect to chemical weapons that's been in place since 1925, if we are unwilling to do that, we will be granting a blanket license to Assad to continue to gas."

He also warned that a retreat from strong US positions against chemical and nuclear weapons would send "a terrible message to the North Koreans, Iranians and others" about whether America was serious about nonproliferation.