The White House said on Monday the defection of Syria's prime minister showed that President Bashar al-Assad's government was “crumbling from within” and it repeated its call for him to step aside and end the violence gripping the country.
Al Arabiya sources said that Riyad Hijab has defected alongside three other ministers.
“This is a sign that Assad's grip on power is loosening. If he cannot maintain cohesion within his own inner circle, it reflects on his inability to maintain any following among the Syrian people that isn't brought about at the point of a gun,” White House spokesman Jay Carney told a news briefing.
“The momentum is with the opposition and with the Syrian people. It's clear that these defections are reaching the highest levels of the Syrian government and Assad cannot restore his control over the country because the Syrian people will not allow it,” he said.
The United States has been seeking to increase pressure on Assad to leave power for more than a year.
On Monday, Syrian television said that Hijab has been fired less than two months after taking post.
President Bashar al-Assad appointed Hijab, a former agriculture minister, as prime minister in June following a parliamentary election in May which authorities said was a step towards political reform but which opponents dismissed as a sham.
Meanwhile, a blast rocked the headquarters of Syrian state television in the heart of Damascus on Monday causing casualties, the broadcaster reported.
“An explosion hit the third floor of the Syrian television headquarters, causing casualties,” it said.
Suhail al-Qassim, a representative from Sham Media Network in Damascus said the regime was being behind the blast. Qassim said the regime did it, so it could appear as the “hope” for Syrians who fear living in an instable country.
He said the regime usually accuses the Free Syrian Army (FSA) or al-Qaeda just to rebuff suspicion that is the one behind the bombings.
The Damascus representative also reported of heavy shelling in the countryside of Damascus. He said mass arrests and searches were taking place in al-Maza area in Damascus.
Meanwhile, Syrian regime forces shelled several areas of the northern city of Aleppo on Monday morning, and shooting was also reported in other neighborhoods of the embattled commercial capital, monitors said.
Around 12 people killed by the Syrian security forces in Aleppo, Al Arabiya reported on Monday.
Clashes in the rebel-held district of Salaheddin killed a rebel commander, the Britain-based Syrian Observatory for Human Rights said.
In related news, regime forces pounded the Palace of Justice in the heart of Aleppo, as well as the Marjeh and Shaar districts, the Britain-based Observatory said.
In Bab al-Nayrab too, regime forces shot dead a civilian while he was helping wounded people, the watchdog added.
A total of nine people were killed in violence in Aleppo on Monday, among them eight civilians, it said.
The NGO also reported another 19 deaths across the country in the early hours of Monday, 13 civilians and six rebels.
On Sunday, 131 people were killed in violence nationwide, the monitoring group said. They were 79 civilians, 42 regime troops and 10 rebels.
It is difficult to independently verify death tolls out of Syria and the United Nations has stopped keeping a toll.