Dubai: US Secretary of State Hillary Clinton has called for "friends of democratic Syria" to unite against President Bashar Al Assad following China's and Russia's veto of a resolution backed by Arabs and the West, which she described as a "travesty".

Western and Arab countries responded with outrage after Russia and China vetoed a UN Security Council resolution.

"What happened yesterday at the United Nations was a travesty," Clinton said.

Burhan Galioun, head of the opposition umbrella Syrian National Council, called Moscow's and Beijing's veto "a new licence to kill from these two capitals for Bashar Al Assad and his criminal regime, which just yesterday killed 300 people."

Arab League head Nabeel Al Arabi said the body still intends to build support for its plan. Arab League foreign ministers will meet in Cairo next Saturday.