BBC: US Secretary of State Hillary Clinton has described as a "travesty" Russia and China's veto of a UN resolution condemning Syria's crackdown against anti-government protesters.
Speaking in Bulgaria, Mrs Clinton said efforts outside the world body to help Syria's people should be redoubled.
The US, she said, would work with "friends of a democratic Syria" to support opponents of Syria's president.
The vetoing of the resolution drew an angry reaction from around the world.
"What happened yesterday at the United Nations was a travesty," Mrs Clinton said in strongly worded remarks during a visit to the Bulgarian capital, Sofia.
"Faced with a neutered Security Council, we have to redouble our efforts outside of the United Nations with those allies and partners who support the Syrian people's right to have a better future," she said.
"We will work to expose those who are still funding the regime and sending it weapons to be used against defenceless Syrians, including women and children."
Mrs Clinton also said the US would work to tighten "regional and national" sanctions against Syria to hamper its ability to use arms against the protesters.
Human rights groups and activists say more than 7,000 people have been killed by Syrian security forces since the uprising began in March.
The UN stopped estimating the death toll in Syria after it passed 5,400 in January, saying it was too difficult to confirm.
The government says at least 2,000 members of the security forces have been killed fighting "armed gangs and terrorists". (+ video) » | Sunday, February 05, 2012
