By Mariam Karouny and Oliver Holmes
BEIRUT, July 5 (Reuters) - In what would be the most high-profile defection from the inner circle of the Syrian leadership, Manaf Tlas, a friend of President Bashar al-Assad and a brigadier in his Republican Guard, was reported on Wednesday to have fled to Turkey.
Tlas, whose father Mustapha was defence minister under Assad's father for 30 years, could not be reached for comment but several sources among the Syrian rebels told Reuters he had quit Damascus and a news website close to Assad's security services quoted a Syrian official saying Tlas was now in Turkey.
Tlas is a rare representative of the Sunni Muslim majority in a political elite and officer corps dominated by Assad's fellow Alawites, and his break with his friend may reflect an erosion of support for the president among wealthy Sunnis, slow to join an uprising driven by their poorer co-religionists.
The Syriasteps website which quoted a "high-level security source" confirming his flight also quoted a security official playing it down: "His desertion means nothing," he said. "If Syrian intelligence had wanted to arrest him it would have."
But a source in the exiled opposition to Assad, who said a relative of Tlas had confirmed his defection to him, said: "It's a very important defection. His brigade is very attached to their general, so we can say the true defection has started."
That source said Tlas had fled Damascus on Tuesday and was in Turkey en route for Paris, where Western and Middle Eastern sponsors of the rebel cause are meeting as the "Friends of Syria" on Friday. The French capital is also the home of Tlas's sister, widow of a billionaire Saudi arms dealer.
A witness in Damascus, who spoke anonymously for fear of the security services, said Tlas's house in the Syrian capital had been ransacked by security agents on Thursday: "They took away everything," the witness told Reuters.
Another opposition source said Tlas was expected to issue a video message soon announcing he was joining the opposition.
His departure alone is unlikely to affect greatly the capability of the Syrian army but will be seized upon by Assad's enemies in the West as well as at home.
A Western diplomat who knew Tlas in Damascus, where the general and his wife pursued a glamorous society lifestyle with interests in the arts, told Reuters: "Manaf does not give the impression that he is a thug. But he mattered in the military.
"His defection is big news because it shows that the inner circle is disintegrating."
Tlas commanded a brigade of the Republican Guard, an elite, praetorian force commanded by Assad's feared brother Maher, one of the architects of a bloody crackdown on 16 months of dissent and rebellion in which more than 15,000 people have been killed.
Friends have said for some time that Tlas, who attended military college alongside the 46-year-old Syrian leader, had grown disillusioned with the crackdown, which hit particularly hard on his ancestral home town of Rastan, where many of his fellow Sunni Muslims have joined the rebel Free Syrian Army.
His father and a brother who is a prominent businessman had already left Syria since the uprising.
The first opposition source said: "He took this decision because since last year he has been in conflict with President Bashar al-Assad over the Syrian regime's decision to use a military solution against the Free Syrian Army.
"He's is furious about that. Because of this, he has been almost a prisoner at his home in Damascus. Assad reinforced security to stop him leaving," the source added.
Syrian troops pushed into the rebel-held northern town of Khan Sheikhoun on Thursday, activists said. They said the security forces killed at least 11 people in an armoured assault from the south at dawn after a fierce bombardment.
"They are burning houses and farms," local activist Abu al-Ghaith al-Khani said, adding that 80 percent of residents had fled.
In a defiant interview with a Turkish newspaper, Assad blamed the revolt on Islamist militants from hostile Arab states and a Western plot to break up Syria or stoke civil war.
"The big game targeting Syria is much bigger than we expected," he told Cumhuriyet daily. "The fight against terrorism will continue decisively in the face of this."
"Everybody was calculating that I would fall in a small amount of time. They all miscalculated," he said. "If I didn't have the people behind me ... I would have been overthrown. How come I'm still standing?"
Saudi Arabia and Qatar have promised to fund Syrian rebels and have long advocated arming them, despite Western misgivings about the wisdom of further militarising the conflict.
Russia, which condemns outside backing for Syrian insurgents whom it regards as dangerous Islamist militants, dismissed suggestions that it might grant Assad political asylum.
Foreign Minister Sergei Lavrov described such rumours as "an attempt to mislead serious people dealing with foreign policy or a lack of understanding of Russia's position".
Moscow has backed a vaguely-worded proposal for a political transition in Syria, but denies this implies removing Assad.
Along with China, it has blocked U.N. Security Council action on Syria, anxious to give no pretext for a Libya-style military intervention - which the West denies contemplating.
A peace plan brokered in April by U.N.-Arab League envoy Kofi Annan never took effect. The head of a 300-strong U.N. mission sent to monitor Annan's ceasefire said the observers must stay in Syria even though there was no truce and violence was reaching an "unprecedented level".
The mission should be restructured to help support political dialogue, said its leader, General Robert Mood.
Assad's forces have killed more than 15,000 people in 16 months of violence, Syrian dissidents and Western leaders say. Damascus says rebels have killed many soldiers and security men.
Syrian forces also shelled the shattered city of Homs and Harasta, a town near Damascus, activists said.
Human rights monitor Rami Abdelrahman said 97 Syrians had been killed on Wednesday, a now common scale of death.
Iraqi Foreign Minister Hoshiyar Zebari said al Qaeda militants were crossing from Iraq into Syria to carry out "terrorist attacks" in support of anti-Assad rebels.
"Most of the suicide bombers, foreign fighters, elements of al Qaeda used to slip into Iraq from Syria. So they know the routes and the connections," Zebari said. "This is our main concern - about the spillover, about extremist groups taking root in neighbouring countries, to have a base."
Al Qaeda leader Ayman al-Zawahri has urged Sunni Muslim militants to join the fight against Assad, whose Shi'ite-rooted minority Alawite sect dominates the army and security forces.
U.N. Secretary-General Ban Ki-moon has said he believes al Qaeda was responsible for two suicide car bombs in Damascus in May that killed at least 55 people.
Tensions on Syria's northern border with Turkey have also soared since Syria shot down a Turkish reconnaissance F4 plane over the Mediterranean on June 22 in disputed circumstances.
Turkey said it had retrieved the two pilots' bodies from the jet's wreckage on the seabed and had flown them back to their base in Malatya for burial on Friday.
Turkey will join Western and Arab states in Paris on Friday for a third meeting of the "Friends of Syria" forum that includes countries opposed to Assad. Moscow and Beijing refuse to attend.
Apart from Russia and China, Assad can also call on the support of Iran.
"The Americans think only of their own interests, but it is the right of the nations in the region, including the great nation of Syria, to freely determine their own destiny, and other nations should not impose their own demands," Iranian President Mahmoud Ahmadinejad said on Thursday. (Additional reporting by Khaled Yacoub Oweis in Antakya, Sylvia Westall in Baghdad, Daren Butler in Istanbul, Jonathon Burch in Ankara, Gleb Bryanski in Moscow, Arshad Mohammed in Washington, Stephen Brown in Berlin, Catherine Bremer in Paris and Marwan Makdisi in Damascus; Writing by Alistair Lyon and Alastair Macdonald; Editing by Peter Graff)