The Arab League called for United Nations and International measures against Syria over alleged gas attack.
Arab Foreign Ministers arrived in Cairo on Sunday for an urgent Arab League meeting to discuss the Syrian crisis and the potential military strike on the country.
Earlier on Sunday, Saudi Arabia's Foreign Minister Saud al-Faisal said it was time for the world to do everything it could to prevent aggression against the Syrian people, and that it would back a U.S. strike on Syria if the Syrian people did.
Faisal made his comments as the U.S. prepares strikes against the Syrian government, blaming it for a chemical gas attack that killed hundreds of civilians.
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Syrian President Bashar al-Assad said on Sunday that Syria was capable of confronting any external attack after U.S. President Barack Obama said there should be a military strike.
On Saturday, Obama formally asked for Congressional approval for a military strike against Syria. Obama will seek lawmakers' consent before giving the order to strike against Assad.
The move makes an anticipated strike not within days as was widely expected, but in mid-September at the earliest and would come after the U.S. blamed Assad's forces for killing some 1,400 Syrian civilians in last month's chemical weapons attack.
U.S. Secretary of State John Kerry asserted Sunday that the United States now has evidence of sarin gas use in Syria and said "the case gets stronger by the day" for a military attack.
A day after Obama stepped back from his threat, Kerry said in a series of interviews in the media on Sunday that the administration learned of the sarin use within the past 24 hours through samples of hair and blood provided to Washington by first responders in Damascus.
Kerry also said he was confident that Congress will give Obama its backing for an attack against Syria, but he also said the president has authority to act on his own if Congress doesn't give its approval.
Assad said on Sunday that Syria was capable of confronting any external aggression and that threats of a U.S. strike would not discourage the country from a fight against what it described as "terrorism."
"The American threats of launching an attack against Syria will not discourage Syria away from its principles ... or its fight against terrorism supported by some regional and Western countries, first and foremost the United States of America," Assad said in his first comments since Obama's speech.
Syria generally refers to rebels fighting to topple Assad as "terrorists."
Syrian Deputy Foreign Minister Faisal Mekdad said on Sunday Obama's speech showed hesitation and confusion.
"It is clear there was a sense of hesitation and disappointment in what was said by President Barack Obama yesterday. And it is also clear there was a sense of confusion as well," he told reporters in Damascus.
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While Kerry stopped short of saying Obama was committed to such a course even if lawmakers refuse to authorize force, he did tell ABC's This Week that "we are not going to lose this vote."
Kerry said Obama has the right to take action against Syria, with or without Congress' approval. But he stopped short of saying Obama was committed to such a course even if lawmakers refuse to authorize force.
Congress is scheduled to return from a summer break on Sept. 9.
Kerry maintained there is no weakness in the U.S. case underscoring Obama's about-face, saying instead that "the president believes that we are all stronger as a nation when we act together."
The secretary said that Assad "has now joined the list of Adolf Hitler and Saddam Hussein" in deploying chemical weapons against his population and that "the case remains the same" for a U.S. response. Kerry echoed Obama in saying the world cannot stand by and watch Assad use chemical weapons.
The UN weapons inspection team left Syria on Saturday and arrived in The Hague, Netherlands. There is no specific timeline for when their analysis will be completed, Nesirky said.
UN Secretary General Ban Ki-moon said the Security Council should stand "firm and united" on any action against use of chemical weapons, according to Nesirky.
Obama changed his mind
Administration officials have said that Obama appeared set on ordering a strike until Friday evening. After a long walk around the White House grounds with Chief of Staff Denis McDonough, the president told his aide he had changed his mind.
These officials said Saturday that Obama initially drew pushback in a two-hour session attended by Vice President Joe Biden, Defence Secretary Chuck Hagel, Director of National Intelligence James Klapper, CIA Director John Brennan, national security adviser Susan Rice and homeland security adviser Lisa Monaco. They declined to say which of the participants had argued against Obama's proposal.
With files from CBC News and Reuters