U.N. Secretary-General Ban Ki-moon is urging world powers to hold off on possible military action against Syria until a U.N chemical weapons inspection team completes its work in the country.
Mr. Ban said Thursday that the team will leave the country by Saturday and report its findings to him.
He said "diplomacy should be given a chance" as the U.S. and other Western powers consider their response to the Syrian government's alleged use of chemical weapons against civilians last week.
The U.N. team left Damascus in a convoy on Thursday to begin its third day of inspections.
British Prime Minister David Cameron is meeting with parliament on Thursday to discuss the Syria situation.
Amid mounting pressure from lawmakers, his government said Wednesday that Britain would not take part in any military action against Syria until the U.N. team had a chance to report its findings.
In Washington, White House officials plan to brief members of Congress, on Thursday, about intelligence on the alleged poison gas attacks that killed hundreds of civilians in Damascus suburbs.
The Syrian government denies having any role in the alleged attacks. And state media reports say Syrian President Bashar al-Assad said Thursday his country would defend itself against any aggression and emerge "victorious."
Iran warned any Western action against Syria would result in the "imminent destruction of Israel," a U.S. ally in the region.
According to Iranian news reports, Revolutionary Guards Major General Mohammad Ali Jafari also said any U.S. action against Damascus would be like a "second Vietnam" for America.
U.S. President Barack Obama says he has not decided on any action, but he has vowed that those who break international norms need to be held accountable.