Russia and China have again vetoed a Western-backed UN resolution threatening non-military sanctions against Syria, meaning it won't be adopted despite appeals for united and concerted action to help end the escalating violence during the 16-month uprising. 

Eleven of the UN Security Council’s 15 members voted in favour of the resolution’s text, while two others – Pakistan and South Africa – abstained. A veto by any one of the council’s five permanent members means a resolution cannot be adopted.

Analysis

Sasa Petricic, CBC News, Mideast correspondent

One of Syrian President Bashar Assad’s main strengths has been the tight-knit loyalty of his inner circle. Much of it – in the military, the security and intelligence departments — is made up of his own minority sect, Syrian Allawites. Some are even related to Assad. Others are trusted representatives of the country's other religious groups.

Together they made up an apparently unshakeable foundation for his regime. Now that foundation has been shown to have serious cracks … and not just because the blast left Assad with gaping holes in his entourage.

If it was an inside job, done with the help of someone who had access to a top-level meeting in one of the most secure buildings in Syria, then all of Assad’s men cannot be trusted.

But there is another theory floating around as well, based on the fact that the regime hasn't provided any evidence of the blast … no pictures, no access to independent journalists. (In fact, when a BBC journalist passed the building soon after the attack was announced, there were no broken windows or other signs of destruction.)

The theory is that some of these top men – reportedly killed in the bombing – were actually murdered earlier, perhaps because of their disloyalty to the regime. The blast was just a way to blame the opposition. There is no hard evidence of this either, but either way, the conclusion is the same. Assad's solid support is crumbling. The defections are well underway.

That leaves in limbo the future of the 300-strong UN peacekeeping force in Syria, whose mandate expires Friday.

It was the third time that Russia, a key ally of the Syrian government, and China have used their veto power to block UN resolutions that would pressure Syrian President Bashar Assad and stop the violence that has killed an estimated 17,000 people.

Britain's UN ambassador, Mark Lyall Grant, who sponsored the draft, said he was "appalled" at the third double veto by Russia and China.

It was a blow to Kofi Annan, the joint UN-Arab League envoy to Syria, who had called for "consequences" for non-compliance with his six-point peace plan, which the Assad government has flouted.

In a statement issued after the vetoes, a spokesman for Annan said Annan is disappointed that "at this critical stage, the UN Security Council could not unite and take the strong and concerted action" he had urged and hoped for."

Annan had requested a delay in Wednesday's vote on the resolution and appealed to the council to unite behind a new resolution, but Moscow wouldn't budge and the West insisted on including the threat of non-military sanctions under Chapter 7 of the UN charter. That could eventually open the door to the use of military force.

UN Secretary-General Ban Ki-moon also expressed disappointment, accusing the Syrian government of failing to protect its people and pledging that with Annan and the UN, he will "spare no effort" in the search to end the violence and bring about a peaceful, democratic Syrian-led transition, UN spokesman Martin Nesirky said.

"The onus is also on the parties, and with the Syrian government in the first place, who must stop the killing and stop the use of heavy weapons against population centres," Ban's spokesman said.

Before the UN session, the chief UN observer in Syria, Maj. Gen. Robert Mood, said his mission was irrelevant without a political process seeking to end the country's civil war. 

Foreign Affairs Minister John Baird issued a statement saying despite the vetoes by Russia and China, Canada will continue to work toward a diplomatic end to the violence, because it is the responsible thing to do.

"It is with extreme disappointment and deep regret that the world witnessed the United Nations Security Council fail the people of Syria yet again today," he said.

"The Security Council had the opportunity to finally do the right thing to enforce a plan through binding sanctions that would have sent a clear message to Assad and those backing him, but, instead, Russia and China chose the status quo. They also chose to ignore the spiralling violence. They failed to act in the most vulnerable hour for the Syrian people."

The violence in Syria continued Thursday with shelling around Damascus a day after a bombing killed three members of Assad's inner circle — an attack that could mark a turning point in the crisis. Anti-regime activists said government troops used mortars, tanks and helicopter gunships against rebels throughout Damascus and its suburbs. But the military's failure to swiftly vanquish lightly armed rebel forces and the deadly bombing of a high-level security meeting a day earlier made Assad's hold on power look increasingly tenuous.

Rebels claimed responsibility, saying they targeted the room where the top government security officials in charge of crushing the revolt were meeting.

Syria's crisis has evolved into a civil war, with scores of rebel groups fighting to topple Assad's regime and an estimated 17,000 people dead.

The whereabouts of Assad, his wife and his three young children were unknown until Thursday, when footage shown on Syrian state TV showed Assad attending the swearing-in of his new defence minister.

State-run TV said Assad, wearing a suit and tie in the footage, gave the new defence minister "instructions" and wished him luck.

With files from CBC News