PARIS, (Reuters) – As a Syrian general who was a personal friend of Bashar al-Assad fled for France, Hillary Clinton urged Assad’s enemies meeting in Paris on Friday to make Russia and China “pay a price” for helping him to keep power in Damascus.

The Secretary of State’s remark, among Washington’s toughest yet in 16 months of revolt, highlighted the gulf between Western and Arab countries, who met opposition groups in Paris to try to engineer Assad’s departure, and his two supporters on the other side of the old Cold War divide, who stayed away from the talks.

“I will tell you very frankly,” Clinton told the Friends of the Syrian People conference, “I don’t think Russia and China believe they are paying any price at all – nothing at all – for standing up on behalf of the Assad regime. 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 because they are holding up progress – blockading it.

“That is no longer tolerable.”

The foreign ministers and senior diplomats from 50 Western, Arab and other countries – including Assad’s former ally and neighbor turned bitter foe Turkey – urged stronger U.N. Security Council action and “broader and tougher” sanctions.

They also agreed to “massively increase” aid to Syria’s rebels and to provide them with communications equipment, according to a final statement. Western powers are reluctant to offer much greater firepower to rebels whose ranks include anti-Western Islamists. Divisions among Assad’s foes, visible notably in a fistfight at an opposition meeting in Cairo this week, have also limited the coordination of efforts to remove him by force.

As Clinton spoke, Manaf Tlas, a brigadier in the Republican Guard who attended military college with Assad and whose father was Assad’s father’s confidant and defense minister for 30 years, was on his way to Paris, the French government said.

There was no immediate sign that Tlas, who friends said had fled Damascus for Turkey this week, would throw in his lot with the rebels. He did not attend Friday’s meeting.

But his defection was the clearest signal yet that some in Assad’s inner circle think his days in power are numbered, as an uprising that began in March 2011 with a groundswell of peaceful protest turns into a civil war with strong sectarian overtones.

Tlas’s father Mustapha now lives in Paris, as does Tlas’s sister. The family has been a rare representative of Syria’s Sunni Muslim majority in an elite dominated by Assad’s fellow Alawites. Sunnis have been in the forefront of the uprising.

DESERTION “MEANS NOTHING”

Assad’s enemies among Syrians and in the West were quick to hail Tlas’s flight as a breakthrough, while Damascus played it down. A Syrian news website quoted a Syrian official on Thursday as saying: “His desertion means nothing … If Syrian intelligence had wanted to arrest him it would have.”

Opposition sources have spoken of senior figures who are under suspicion of being potential defectors being held under virtual house arrest. Assad’s opponents have been trying to encourage as many of his entourage as possible to abandon him.

While the lightly armed rebels are no match for Syria’s large and well-equipped army, their hope lies in eroding loyalty and conviction within Assad’s establishment to the point where it loses its hold on power.

Syria’s army took control of the rebel stronghold of Khan Sheikhoun in northern Idlib province on Friday after an assault on the town backed by helicopters, rebels said.

“The Free (Syrian) Army withdrew from the town last night after it ran out of ammunition. Assad’s army is in control,” said Abu Hamam, a rebel spokesman who fled to a nearby village.

“They are burning the houses. They have burned my own house. I see the smoke covering the sky from where I am now.”

Army shelling and assaults also killed three people in the southern province of Deraa, where the nationwide revolt began.

Opposition activists say more than 15,000 people have been killed in the uprising, while the government says several thousand members of the security forces have died.

The host of the Paris meeting, French President Francois Hollande, said Assad’s departure was “in the interest of Syria, of its neighbors and everybody who wants peace in the region”.

Clinton repeated a U.S. and French call for a U.N. Security Council resolution under Chapter 7 of the U.N. Charter, which allows the Council to authorize actions ranging from diplomatic and economic sanctions to military intervention:

“We should go back and ask for a resolution in the Security Council that imposes real and immediate consequences for noncompliance, including sanctions under Chapter 7,” she said.

Western governments have shown no appetite for military intervention like the NATO bombing that helped oust Libya’s Muammar Gaddafi last year, and U.S. officials have repeatedly said in the case of Syria they are talking only about sanctions.

Russia and China have in the past vetoed U.N. Security Council resolutions designed to pressure Assad, and say they are committed to a peace plan drafted by international envoy Kofi Annan that proposes dialogue without calling for Assad to go.

PLAN STILLBORN

That plan has been stillborn because the ceasefire that was supposed to precede it in April never took hold. Peace monitors effectively gave up on their mission last month after just weeks in Syria as it became clear there was no peace to monitor.

With heavy fighting now on the outskirts of the capital, events on the ground are outrunning diplomatic initiatives.

A senior French diplomat said recent rebel territorial gains had led to signs that even Moscow was now envisaging a post-Assad Syria, something Russian officials strongly deny.

“The situation on the ground has changed fast over the past three weeks, with security forces having no access to some areas,” the French diplomat said. “We are now hearing things from within political and military circles in Russia that are surprising us and that we were not hearing before.”

Tlas’s defection may indicate a growing alienation among the Sunni business elite, which had been slow to embrace the revolt which began among poorer parts of the majority community.

Opposition activists said Tlas would announce that he had abandoned Assad because of anger at civilian deaths. A witness in Damascus said by phone that Tlas’s house in Damascus had been ransacked by security agents after reports that he had fled.

French Foreign Minister Laurent Fabius said the defection meant that Assad’s inner circle “is beginning to understand that the regime is unsustainable”.

Foreign Minister Ahmet Davutoglu of Turkey, Syria’s NATO-member neighbor, agreed: “Every day, generals, colonels, officers are coming, and we have, I think, around 20 generals and maybe 100 high-ranking officers, colonels,” he told France 24 television.

Turkey has moved artillery and troops towards its border with Syria in the two weeks since Syria shot down a Turkish warplane at the frontier. Turkey now says it will treat Syrian units that approach the border as hostile.

Saudi Arabia and Qatar want to fund and arm the rebels, but Western powers have misgivings about sending more weapons into what could become a wider sectarian conflict.

Qatari Prime Minister Sheikh Hamad bin Jassim al-Thani called in Paris for the Security Council, where Russia and China have the power to veto any action, to be sidestepped.

“Are we able to do something outside the Security Council?” he asked. “Yes. Have we done things outside the Security Council in the past? Yes, and there are many examples.

“We are ready to take part in any effort of any kind to free the Syrian people of this tragedy they are in.”

While Syria’s rebels enjoy wide popular sympathy among fellow Arabs, the support of the Sunni-ruled, pro-Western Gulf monarchies also reflects their strategic goal of thwarting the regional ambitions of Assad’s sponsors in Shi’ite-ruled Iran.