International leaders Friday urged the UN to ratchet up pressure on Syrian President Bashar al-Assad by threatening tough sanctions, as the defection of a top general rocked his inner circle.
Some 100 nations and organisations meeting in Paris called on the UN Security Council to adopt a transition plan for Syria backed by economic sanctions if the regime refuses to comply.
US Secretary of State Hillary Clinton issued a clarion call for all nations to do more to push for political change in Syria and end the 16-month conflict, while lambasting Russia and China for "blockading" progress.
The Friends of Syria talks in the French capital took place amid news that a general from Assad's most trusted inner circle had defected in what would be a major blow to the regime as it battles the opposition.
"General Munaf Tlass defected three days ago," a source close to the Syrian government said on condition of anonymity.
Tlass, the highest-ranking military officer to have abandoned the regime, was on his way to Paris to join his wife and his sister, Nahed Ojjeh, widow of Saudi millionaire arms dealer Akram Ojjeh, said the source.
A general in the elite Republican Guard charged with protecting the regime, he is the son of former defence minister Mustafa Tlass, a close friend of Assad's late father and predecessor, Hafez.
"A senior official from the Syrian regime, a commander in the Republican Guard, has defected and is headed for Paris," French Foreign Minister Laurent Fabius confirmed, although the final destination was unclear.
Participants at the Paris meeting called on the UN Security Council to urgently adopt the six-point peace plan drawn up by UN-Arab League envoy to Syria Kofi Annan under the UN Charter's Chapter 7.
But the final statement stressed that any immediate action under Article 41 provided only for non-military intervention.
French President Francois Hollande also pushed for the Security Council to get tough with Damascus, while the Syrian opposition called for humanitarian corridors and a no-fly zone.
The Annan plan, which insists on a cessation of violence by all sides, has made little headway and activists say an estimated 16,500 people have now died since the uprising began in March last year.
"We should go back and ask for a resolution in the Security Council that imposes real and immediate consequences for non-compliance, including sanctions," ranging from economic measures to military force, Clinton said.
In some of her toughest comments yet, Clinton said she thought Russia and China did "not believe they are paying any price at all for standing up on behalf of the regime".
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"The only way that will change is if every nation represented here directly and urgently makes it clear that Russia and China will pay a price. They are holding up progress, blockading it. That is no longer tolerable," Clinton said.
Russia reacted immediately, with Deputy Foreign Minister Sergei Ryabkov "categorically" rejecting "the formulation that Russia supports Bashar al-Assad's regime in the situation that has developed in Syria".
Although Moscow did not attend the meeting, a diplomatic source insisted that "Russian political and security circles are changing their position".
"They agree that the situation is deteriorating... even if they continue to defend Moscow's policies," the diplomat said on condition of anonymity.
UN chief Ban Ki-moon in New York called on the Security Council to consider reducing the number of unarmed military observers in Syria and put more stress on political efforts to end the conflict.
The latest defection comes two weeks after a colonel in the privileged Syrian air force won political asylum after landing his MiG-21 fighter in neighbouring Jordan.
"This is a major blow to the Assad regime," Abdel Basset Sayda, the head of the main opposition Syrian National Council, told journalists in Paris.
"We cannot comment where he is. We are going to seek some cooperation with him. We call for other defections."
The Pentagon hailed Tlass's defection, saying it signals cracks in Assad's inner circle. "We welcome this defection and we believe it is significant," Pentagon spokesman Captain John Kirby told reporters.
Clinton also warned remaining Syrian army and regime members: "It is time to abandon the dictator, embrace your countrymen and women and get on the right side of history."
Sources close to Tlass say his family is now in Dubai while others said he would soon head to Paris.
The Britain-based Syrian Observatory for Human Rights said at least 53 people were killed across Syria on Friday -- 35 civilians, 14 soldiers and four rebels -- as protesters took to the streets in several provinces after being urged to call for a "People's liberation war."
The watchdog reported demonstrations in several provinces across Syria, including in Damascus and Aleppo, the country's commercial hub.
Morocco will host the next Friends of Syria meeting, but no date has been set.