China's and Russia's refusal to back a United Nations Security Council resolution to oust President Bashar Assad is a throwback to the Cold War, some said Sunday.

The vetoes by the two countries snuffed out an Arab League plan for Assad to relinquish power to his vice-president and clear the way for the creation of a unity government. The resolution would have reinforced support for the Arab League plan, which Assad rejected.

"Russia and China did not vote based on the existing realities but on a more reflexive attitude against the West or against certain demands," Turkish Foreign Minister Ahmet Davutoglu said Sunday.

Now with another diplomatic option unattainable many feel that force might be the only way to remove Assad from power and end 11 months of bloodshed.

It has also raised fears that violence could escalate.

The UN estimates more than 5,400 people have been killed since March, and opponents of the regime fear that Assad will be encouraged by a feeling that he is protected by his top ally Moscow and unleash even greater violence to crush protesters.

U.S. Secretary of State Hillary Rodham Clinton called for "friends of democratic Syria" to unite to "support the Syrian people's right to have a better future."

Clinton warned that the likelihood of "a brutal civil war" would increase as Syrians under attack from their government move to defend themselves, unless international steps provide another way.

Speaking to reporters in the Bulgarian capital of Sofia, she called the double veto at the UN Security Council on Saturday "a travesty."

"Faced with a neutered Security Council, we have to redouble our efforts outside of the United Nations," she said.

Clinton's call suggests the formation of a formal group of like-minded nations to co-ordinate assistance to the Syrian opposition, similar but not identical to the Contact Group on Libya, which oversaw international help for opponents of the late deposed Libyan leader Moammar Gadhafi.

U.S. officials said an alliance would work to further squeeze the Assad regime by stepping up sanctions against it, bringing disparate Syrian opposition groups inside and outside the country together, providing humanitarian relief for embattled Syrian communities and working to prevent an escalation of violence by monitoring arms sales.

Indeed, the timing of Russia's and China's defiance also proves awkward for Prime Minister Stephen Harper as he leads a delegation to China later this week.

Canadian officials said China's vote on Syria would be raised, but not in public.

"I think both the prime minister and I will have a full ranging and open and honest discussion with our Chinese counterparts as we always do," Foreign Affairs Minister John Baird told CTV's Question Period. "I think we're better to engage than to sit on the sidelines, so we look forward to arriving in Beijing and some important meetings for Canada,"

Fears abound that if the opposition in Syria turns to armed resistance, the result could be a dramatic increase in bloodshed.

This was evident on Sunday as at least 30 civilians were killed, including five children and a woman who was hit by a bullet while standing on her balcony as troops fired on protesters in a Damascus suburb, according to the Britain-based Syrian Observatory for Human Rights, an activist group.

Government forces firing mortars and heavy machine-guns also battered the mountain town of Zabadani, north of Damascus, a significant opposition stronghold that fell under rebel control late last month. Bombardment the past two days has wounded dozens and forced scores of families to flee, an activist in the town said.

And the commander of the Free Syrian Army told The Associated Press that, after the vetoes at the UN, "there is no other road" except military action to topple Assad.

"We consider that Syria is occupied by a criminal gang and we must liberate the country from this gang," Col. Riad al-Asaad said, speaking by telephone from Turkey. "This regime does not understand the language of politics. It only understands the language of force."

But those loyal to Assad cheered the move by Russia and China and hailed it as a snub to the western powers.

"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 "decisively and militarily against those armed criminals."

With files from The Associated Press