PARIS (Reuters) - France will step up aid to Syria's opposition if the United States Congress votes against a military strike to punish Syria's president for carrying out a reported chemical attack, President Francois Hollande said on Tuesday.
Hollande has been one of the main international voices calling for military action against Syria over the chemical attack, which he and Washington say killed thousands of people in Damascus on August 21.
But he was left out on a limb after Britain's parliament voted against taking part in any action and U.S. President Barack Obama said he would seek Congress approval before any assault.
"If the (Congress) decision is not positive then we would not act alone but we would shoulder our responsibilities, by supporting the Syrian opposition in a way that would provide a response," Hollande said.
Hollande said he was still hoping for the formation of a broad international alliance against Assad, made up of European and Arab states and, ideally, the United States.
"I am waiting for the answer (from the United States) as this will have consequences for the coalition we will have to create," he told journalists.
Foreign ministers from Russia, the United States, France, China, Turkey and other states will meet on the sidelines of the G20 summit in St Petersburg on September 5 and 6 to discuss Syria, diplomats said on Tuesday.
Ahead of that, European foreign ministers and U.S. Secretary of State John Kerry will meet informally in the Lithuanian capital of Vilnius.
(Reporting by John Irish; Editing by Andrew Heavens)