Syria's opposition appealed for international backing today, a day after Russia and China vetoed a UN Security Council resolution aimed at pressuring President Bashar Assad to end his bloody crackdown on an uprising that has raged for almost 11 months.

The double-veto at the Security Council outraged the US and its European allies as well as Arab leaders, and intensified fears among regime opponents that Assad will now unleash even greater violence to crush protesters, feeling that he has protection by his top ally Moscow.

A Syrian state-run newspaper vowed today that Damascus will continue its crackdown on the uprising until stability is restored.

Early yesterday, regime forces bombarded the restive central city of Homs in what activists said was the deadliest incident of the uprising.

They reported more than 200 killed, but the regime denied any bombardment and there was no way to independently confirm the toll.

In new reports of violence today, the UK-based activist group Syrian Observatory for Human Rights said troops and army defectors clashed in the north-western province of Idlib and the southern province of Daraa and said nine soldiers were killed in Idlib.

The Observatory also said that one person was shot dead by a sniper today in the central city of Homs, a hotbed of anti-regime activism. Another activist group, the Local Coordination Committee, said nine people were killed today in different parts of the country.

The Russian and Chinese vetoes at the Security Council effectively killed an Arab League plan aimed at ending the violence in Syria that called for Assad to hand over his powers to his vice president and allow creation of a unity government. The resolution would have expressed support for that Arab League plan, putting pressure on Assad, who has rejected it.

Hundreds of regime supporters held a rally in a Damascus square, waving Russian and Chinese flags in gratitude for their blocking the resolution.

"Thanks Russia, thanks China for undermining the Western conspiracy against our country," said Nibal Hmeid, a 24-year-old teacher at the rally. She said Assad should now settle the situation in Syria "decisively and militarily against those armed criminals".

The regime has painted the uprising as the work of terrorists and armed gangs as part of a foreign conspiracy.

Proponents of the Arab League plan are now searching for an alternative to address Syria's crisis, which the US and many European countries have said bluntly can only be resolved by Assad's leaving power.

"The veto is not the end of the world. The revolution will continue and it will be victorious, God willing," Radwan Ziadeh, a prominent figure on the Syrian National Council, the main opposition umbrella group, wrote on his Facebook page.

After 13 of the Security Council's 15 members backed the resolution, he said, countries backing Syria's opposition should form an "international coalition... whose aim will be to lead international moves to support the revolution through political and economic aid".

Ziadeh said he expected French, US and Arab support for a coalition.

A deeply sensitive question is whether such a coalition would back the Free Syrian Army, a force of army defectors who in recent months have gone beyond protecting protesters in Syria to launching attacks on regime forces and trying to establish overt control in pro-opposition parts of the country.

There appears to be deep hesitation among Western countries to back them, fearing that as Assad cracks down, the opposition could turn more to force of arms and the country could be torn by outright civil war.

In an interview with Al-Arabiya TV yesterday, the head of the Syrian National Council Burhan Ghalioun also spoke of an international coalition but sought to avoid talk of military support for the rebel fighters. However, he did say such support was possible "if necessary" to "protect the Syrian people".

More than 5,400 people have been killed in Syria's crackdown, according to a UN count from January that has not been updated, and activists have reported dozens killed daily since.