US Secretary of State Hillary Clinton has described as a "travesty" Russia and China's veto of a United Nations resolution condemning Syria's crackdown on anti-government protesters.
Diplomatic efforts to end the violence in Syria that began 11 months ago have moved away now from the UN, the BBC reports.
Speaking in Bulgaria, Mrs Clinton said the UN Security Council had been neutered by the veto and efforts outside the world body to help Syria's people should be redoubled.
The US would work with "friends of a democratic Syria" to support opponents of Syria's president Bashar al-Assad, she said.
The BBC reports Mrs Clinton seems to be talking about the formation of something like the contact group on Libya.
It oversaw international help for opponents of Muammar Gaddafi and also coordinated NATO military operations to protect Libyan civilians during an uprising there - something not envisaged for Syria.
China and Russia's vetoing of the resolution on Saturday drew an angry reaction from around the world.
Meanwhile, there are reports of renewed fighting in Homs, where regime forces are said to have killed scores of people at the weekend.