Syrian opposition forces have been mobilizing Prime Minister Riyad Hijab and some ministers for the last four months, an opposition official told the Global Times after Hijab reportedly fled the country on Monday and defected to the opposition seeking to overthrow President Bashar al-Assad.

Syrian state television said Hijab had been fired, but an official source in the Jordanian capital Amman said he had been dismissed only after he fled across the border with his family.

"I announce today my defection from the killing and terrorist regime and I announce that I have joined the ranks of the freedom and dignity revolution," Hijab said in a statement read in his name by the spokesman, broadcast on Al Jazeera TV. "I announce that I am from today a soldier in this blessed revolution."

Several media reports indicated on Monday that Hijab entered Jordan after he defected along with several family members and ministers. But Jordan's Minister of State for Media Affairs and Communications Samih Maaytah on Monday said Hijab has not entered Jordanian territory as of press time, the state-run Petra news agency reported. Al Arabiya TV channel said Hijab was to leave Jordan for Qatar.

Bikar Atlcan, a member of the opposition Syrian National Council, told the Global Times on Monday that the opposition and "friends from other countries" have been trying for months to persuade almost every senior Sunni official in the government to defect.

"What they are most worried about is the safety of their families," said Atlcan. "Our foreign friends set up very detailed plans and send people to Syria and accompanied the officials to flee country."

Atlcan said Hijab and his two brothers, respectively heads of the environment ministry and oil ministry, and seven other family members, had run away after pretending to gather for dinner.

Li Weijian, director of the Institute for Foreign Policy Studies of the Shanghai Institutes for International Studies, noted the betrayal of high-profile officials dealt a heavy blow to the peace process in Syria.

"It will inspire the opposition forces and encourage the Western countries who support the opposition forces to provide more tempting offers to further disintegrate the Syrian forces," Li told the Global Times.

However, Li said it is difficult to tell if or when Assad will give up power. "The final decision is in the hands of the Syrian people," Li said.

The defection of Hijab is considered another sign of the increasing political pressure that the Syrian leadership faces from within, Xinhua reported.

Liang Chen and agencies contributed to this story