Syrian Prime Minister Riyad Hijab has been sacked, state television reported on Monday, and an official source in Amman said he has defected with his family to neighbouring Jordan.Syrian state TV announced Hijab’s dismissal as government forces appeared to prepare a ground assault to clear battered rebels from Aleppo, the country’s biggest city.President Bashar al-Assad appointed Hijab, a former agriculture minister, as prime minister only in June following a parliamentary election which authorities said was a step towards political reform but which opponents dismissed as a sham."Hijab is in Jordan with his family,” said the Jordanian official source, who did not want to be further identified.Syrian TV said Omar Ghalawanji, who was previously a deputy prime minister, had been appointed to lead a temporary caretaker government on Monday.Earlier in the day, a bomb blast hit the Damascus headquarters of Syria’s state broadcaster 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.