The defection of Syrian Prime Minister Riad Hijab, the highest-ranking government leader to abandon beleaguered President Bashar Assad, is another body blow for the minority regime in Damascus that has lost several key figures in recent weeks.

But virtually all the generals, ministers and diplomats who've deserted the Assad dynasty, dominated by member of the minority Alawite sect, have been Sunni Muslims, who comprise about 74 percent of Syria's population of 22.5 million.

Amid the Syrian bloodbath, which began in March 2011 as an uprising against Assad's rule and morphed into a murderous civil war, the Alawites appear to remain loyal to Bashar, a former London eye doctor who inherited power in 2000.

How long that will be the case is anybody's guess, particularly as the pace of defections seems to be accelerating.

Hijab, a Sunni from the Deir al-Zour region of eastern Syria that's been heavily shelled by the regime, is the first Cabinet minister to defect since senior figures began to abandon the regime earlier this year.

But he's a puppet figure.

Widely seen as a staunch loyalist of the ruling Baath party, Hijab was appointed prime minister by Assad on June 6 following "general elections" that were part of Assad's supposed reform process.

He has periodically engaged in such exercises in an apparent attempt to be seen to be prepared to make political changes, though none of these steps have addressed the rebels' main demand for the end of the 42-year regime.

Hijab said in a statement issued by his spokesman, Mohammed el-Etri, "I have defected from the terrorist, murderous regime and I am joining the holy revolution."

Etri told the BBC the regime is "now in its last throes" and had been dealt "a fatal blow" by Hijab's action.

"This defection was not a matter of days or weeks, it was in the pipeline for two months through a trusted cell close to the prime minister made up of rebels and aides," Etri said.

However, Assad is showing no sign of throwing in the towel, even though he suffered his most grievous blow to date July 18 with the assassination of four of his closest security chiefs, including his brother-in-law, in a highly secure building in a heavily guarded district of Damascus.

"For months the regime has been eroding and shedding its outer layers, while rebuilding itself around a large, diehard fighting force," said analyst Peter Harding of the International Crisis Group, a conflict resolution group.

"The regime as we knew it is certainly much weakened but the question remains of how to deal with what it's become."

The audacious July 18 bombing, which wiped out most of Assad's inner security circle, indicated the rebels have penetrated the regime's core, a weak spot that could be exploited further.

In recent months, some 40 generals have defected, mainly to Turkey where the rebel Free Syria Army is based and aided by the Ankara government.

Assad's forces have recaptured most of the sections of Damascus that rebels overran recently and are pressing hard to oust the FSA and its allies from the northern city of Aleppo, Syria's commercial hub and vital to the regime.

But it's only 40 miles south of the border with Turkey, from where rebel reinforcements and weapons, widely believed to be supervised by Turkish, U.S., Saudi Arabian, French and British intelligence services, are constantly moving.

The regime's key military units, particularly the elite Republican Guard commanded by Maher Assad, the president's hot-headed younger brother, and the intelligence services remain intact and supposedly loyal.

All these are overwhelmingly Alawite and have been responsible for slaying of thousands of people through indiscriminate shelling and systematic execution in the regime's withering crackdown.

These diehards, like their leaders, have nowhere to run if the regime falls apart, and they may well fight to the death.

These forces still outgun and outnumber the rebel groups, although these are acquiring increasingly effective weapons largely funded by the Sunni monarchies of Saudi Arabia and Qatar.

These royal houses are bitterly opposed to the Damascus regime because of its 30-year alliance with Shiite Iran.

The Islamic Republic and Russia are Assad's only allies and there are signs they're getting jittery about Assad's prospects for survival.

What they do in the days ahead is more likely to influence events than a few defections.