The United States is considering launching a punitive strike against the regime of Syrian President Bashar Assad, blamed by the U.S. and the Syrian opposition for an Aug. 21 alleged chemical weapons attack in a rebel-held suburb of the Syrian capital of Damascus.
The U.S. has said a sarin gas attack killed 1,429 people, including more than 400 children, based on intelligence reports. The Britain-based Syrian Observatory for Human Rights, which collects information from a network of anti-government activists in Syria, said it has been compiling a list of the names of the dead and that its toll has reached 502.
President Barack Obama said he has decided that the United States should take military action against Syria but is seeking congressional authorization for the use of force in a vote expected after Congress returns to work Sept. 9.
Here's a look at key Syria developments around the world Thursday amid heightened tensions over potential military action:
Leaders at the forefront of the geopolitical standoff over Syria's civil war gathered in St. Petersburg and started the two-day meeting of the Group of 20 leading world economies, with the threat of missiles over the Mediterranean eclipsing economic issues that usually dominate the annual summit. Differences over Syria have heightened tensions between Obama and Russian President Vladimir Putin since the civil war in Syria started in 2011.
Putin's spokesman, Dmitry Peskov, said the U.S. should wait for the U.N. inspectors' report on their investigation into chemical attack before intervening militarily, adding that Washington's evidence of Syrian regime involvement isn't strong enough. He insisted the U.N. Security Council is the only body that can authorize use of force. The Kremlin's chief of staff said Russia has been sending warships to the Mediterranean Sea for possible evacuation of Russian citizens from Syria. Sergei Ivanov told Russian news agencies the country boosted its naval presence "primarily" to organize a possible evacuation.
Prime Minister David Cameron said British scientists have found new evidence that poison gas was used last month outside the Syrian capital. Cameron told BBC television the evidence being examined at England's Porton Down Laboratory "further shows the use of chemical weapons in that Damascus suburb."
Syrian government troops battled al-Qaida-linked rebels for a second day over the regime-held Christian village of Maaloula in western Syria. Rami Abdul-Rahman, the director of the Britain-based Observatory for Human Rights, said the fighters included members of the of al-Qaida affiliated Jabhat al-Nusra group.
Obama pressed skeptical lawmakers in phone calls from St. Petersburg to give him the authority to use U.S. military force against Syria while the administration. Obama's advisers were lobbying Congress in closed-door meetings for military strike authorization.