Former Syrian Prime Minister Riyad Hijab has defected to Jordan, a Jordanian official source said on Monday.
"Hijab is in Jordan with his family," said the source, who did not want to be further identified.
Syrian President Bashar Assad appointed Riyad Hijab, a former agriculture minister, as prime minister only in June following a parliamentary election that authorities said was a step towards political reform but which opponents dismissed as a sham.
Riyad Hijab (left) is sworn in as new Syrian Prime Minister by President Bashar Assad in Damascus, in June 26, 2012.
Earlier on Monday, a bomb blast hit the Damascus headquarters of Syria's state broadcaster on as troops backed by fighter jets kept up an offensive against the last rebel bastion in the capital.
The bomb exploded on the third floor of the state television and radio building, state TV said. However, while the rebels may have struck a symbolic blow in their 17-month-old uprising against Assad, Information Minister Omran Zoabi said none of the injuries was serious, and state TV continued broadcasting.
Rebels in districts of Aleppo visited by Reuters journalists seemed battered, overwhelmed and running low on ammunition after days of intense tank shelling and helicopter gunships strafing their positions with heavy machinegun fire.
Emboldened by an audacious bomb attack in Damascus that killed four of Assad's top security officials last month, the rebels had tried to overrun the Damascus and Aleppo, the country's commercial hub.
But the lightly armed rebels have been outgunned by the Syrian army's superior weaponry. They were largely driven out of Damascus and are struggling to hold on to territorial gains made in Aleppo, a city of 2.5 million.
Damascus has criticised Gulf Arab states and Turkey for calling for the rebels to be armed, and state TV has described the rebels as a "Turkish-Gulf militia", saying dead Turkish and Afghan fighters had been found in Aleppo.
Paralysis in the UN Security Council over how to stop the bloodshed forced peace envoy Kofi Annan to resign last week, his ceasefire plan a distant memory.
The violence has already shown elements of a proxy war between Sunni and Shi'ite Islam which could spill beyond Syria's border. The rebels claimed responsibility for capturing 48 Iranians in Syria, forcing Tehran to call on Turkey and Qatar - major supporters of the rebels - to help secure their release.
Also on Monday, Syrian army tanks shelled alleyways in Aleppo where rebels sought cover a helicopter gunship fired heavy machinegun fire.
Snipers ran on rooftops targeting rebels, and one of them shot at a rebel car filled with bombs, setting the vehicle on fire. Women and children fled the city, some crammed in the back of pickup trucks, while others walked on foot, heading to relatively safer rural areas.