Syrian Prime Minister Riyad Hijab has defected to Jordan, according to news reports, becoming the most senior official yet to quit the embattled government. (Khaled al-Hariri/Reuters)

Syria’s prime minister defected to Jordan on Monday, according to rebels who claim they helped him escape, becoming the most senior official to quit the embattled government of President Bashar al-Assad.

The reported defection of Prime Minister Riyad Hijab buoyed the rebels, who saw it as a clear sign that top officials are abandoning Assad as he attempts to crush a persistent 17-month-long uprising.

A statement attributed to Hijab and read on the al-Jazeera Arabic news channel said he had resigned to protest his government’s harsh tactics in confronting the opposition.

“I am announcing that I am defecting from this regime, which is a murderous and terrorist regime,” the statement said. “I join the ranks of this dignified revolution.”

Real power in Syria is wielded by Assad’s inner circle of friends, family and the powerful chiefs of his security forces. But the defection of the head of Assad’s government nonetheless sent a strong signal that his support is rapidly unraveling even within the ranks of those assumed to still be loyal.

Hijab, a former agriculture minister and a member of the ruling Baath Party, is a Sunni Muslim from the eastern town of Deir al-Zour, which has been in open revolt against the government for more than a year.

Reuters news service quoted an unidentified Jordanian government official as confirming that Hijab had defected and taken refuge there. Syrian state television, however, reported that Hijab had been fired, less than two months after he was appointed to the job. Deputy Prime Minister Omar Galawanji was appointed as the head of a caretaker government, according to the official Syrian Arab News Agency (SANA).

Hijab’s departure followed an accelerating stream of defections from Syria’s armed forces, including that of Brig. Gen. Manaf Tlas, a former confidant and close friend of Assad’s who fled to Turkey a month ago, then went to France to join his father, a once-powerful former defense minister.

A senior State Department official traveling with Secretary of State Hillary Rodham Clinton in South Africa said that the defection, if confirmed, would represent “further evidence that the Assad regime is crumbling.’’

“Its days are numbered, and we call on other senior members of the regime and the military to break with the bloody past and help chart a new path for Syria — one that is peaceful, democratic, inclusive and just,’’ the senior State Department official said.

The Syrian military blasted Damascus and at least half a dozen cities around the country Monday with artillery as fierce clashes rocked the northern city of Aleppo, the country’s largest. At least 116 people were killed across Syria on Monday, including 30 in Aleppo and 29 in Damascus and its suburbs, according to the Local Coordination Committees, an activist network.

In Damascus, a bomb exploded Monday in the state television offices, causing minor injuries, according to SANA. Photos taken after the blast, which hit the third floor of the building, showed a demolished roof with wires hanging down.

The complicated operation to get Hijab out of the country was completed in a series of carefully planned steps by the Free Syrian Army, according to Col. Malik Kurdi, a deputy commander with the rebel force.

“The prime minister and his family were transferred outside Syria to Jordan by separate vehicles and at different times,” Kurdi said. “The defectors cannot leave in an hour or a day. The process takes a long time, and there are many phases and routes.”

Jordanian authorities may not have initially known about Hijab’s entry into the country because he was brought via smuggling routes, Kurdi said. But Jordanian contacts eventually met him once he crossed the border. Kurdi predicted that the successful escape would lead to more defections among other top officials who have been thinking of leaving the country.

Iran, Syria’s closest ally, plans to host a meeting in Tehran on Thursday to discuss options for resolving the crisis in Syria, according to the official Islamic Republic News Agency. Among the issues likely to be discussed is the fate of a group of 48 Iranians captured in Syria on Saturday.

The Iranian government has said that the kidnapped Iranians are pilgrims who were on their way to Sayida Zeinab, a Muslim shrine south of Damascus that is popular with Shiites. But rebels assert that the captives belonged to Iran’s elite Revolutionary Guard Corps.

Sly reported from Antakya, Turkey. Anne Gearan in South Africa, Greg Miller in Washington, and Suzan Haidamous and Ahmed Ramadan in Beirut contributed to this report.