A rebel commander of the Free Syrian Army fires towards a pro-government sniper in the Salaheddin district of the northern city of Aleppo.
In his first public appearance since he fled Damascus with his family a week ago, Hijab urged other top officials to follow his example and defect. He told a press conference in the Jordanian capital, Amman, the Syrian army needed to "take the side of the people".
"I assure you, from my experience and former position, that the regime is collapsing, spiritually and financially, as it escalates militarily," Hijab said. "It no longer controls more than 30% of Syrian territory."
Hijab said while he was prime minister he had been unable to stop the regime using heavy artillery against Syrian cities it considered opposition strongholds. He said he had felt "pain in my soul" at the shelling of civilian areas.
"I was powerless to stop the injustice," he said. But he added: "Syria is full of honourable officials and military leaders who are waiting for the chance to join the revolution. I urge the army to follow the example of Egypt's and Tunisia's armies and take the side of people."
In Damascus, the regime shrugged off Hijab's defection and his new claims. Kadri Jamil, one of four deputy prime ministers in Syria's government, told the Guardian that Hijab's defection had been a surprise and that here had been no inkling from the views he expressed in Cabinet that he was about to become a critic.
'Natural selection'
"He was a good actor. He wasn't truthful with us. He was a double-faced person," Jamil said, arguing that such defections could have a positive impact for the government.
"There's a process of natural selection going on within the regime. It should have started long ago. The regime didn't have the courage to do it, but events have done it. All the corrupt elements within the regime are leaving the ship because they think it's sinking."
He also hinted that foreign intelligence services had helped Hijab to defect.
Opposition figures claim many other leading military and political figures in the regime have swapped sides but remained at their posts, either out of fear of what would happen to their families if they defected, or because they had been asked to stay by the rebels to supply intelligence on the inner workings of Assad's government.
Hijab is the highest-ranking defector to date. His flight from Damascus came a month after the defection of a Republican Guard general and former member of Assad's inner circle, Manaf Tlass, and the Syrian ambassador to Baghdad, Nawaf al-Fares.
In the past week the head of protocol at the presidential palace, Muhi al-Din Maslaman, has also defected.
Vocal objections
Leaders of Muslim countries are expected to suspend Syria's membership of the Organisation of Islamic Cooperation at a summit in Mecca on Wednesday, despite the vocal objections of Assad's main ally, Iran.
The decision by the 57-member organisation, which requires a two-thirds majority, will expose the divisions within the Islamic world over how to respond to civil war in a country that straddles the Middle East's main sectarian fault line.
In an apparent conciliatory gesture, Saudi state TV showed King Abdullah welcoming leaders to the summit with Iran's President Mahmoud Ahmadinejad at his side. Abdullah and Ahmadinejad were shown talking and laughing together.
"It was a message to the Iranian nation and, I assume, to the Saudi people, that we are Muslim and we have to work together and forget about our differences," said Abdullah al-Shammari, a Saudi political analyst.
Syria's mainly Sunni Muslim rebels are backed by Sunni-ruled Arab states such as Saudi Arabia and Qatar, as well as Turkey, while Shi'ite Iran supports Assad – a member of the Alawite minority sect which is an offshoot of Shi'a Islam.
Diplomatic efforts
Those divisions have stymied diplomatic efforts to halt the bloodshed in Syria, where opposition sources say 18 000 people have been killed, and have raised the prospect of Syria becoming a proxy battlefield for outside powers.
Curbs on media access make it hard to know how much of Syria is in rebel hands, but most towns and cities along the country's backbone, a highway running from Aleppo in the north to Dera'a in the south, have been swept up in the violence, and Assad has lost swathes of land on Syria's northern and eastern border.
Hijab's defection prompted Washington to announce on Tuesday that it was removing him from a list of Syrian officials targeted by financial sanctions.
The fighting in recent weeks has been focussed mainly on Aleppo, Syria's economic dynamo, where rebels have been holding out against government bombardment and air strikes.
Reuters journalists in Aleppo heard shelling and explosions in Saif al-Dawla district, next to the Salaheddine neighbourhood which has seen some of the heaviest fighting in the last two weeks. One rebel fighter was killed by tank shelling, his bloodied body dragged out of the line of fire by comrades.
Uprooted
"We received some simple amounts of ammunition but it is not enough," said rebel fighter Hossam Abu Mohammad, a former army captain. "We need specific kinds of [anti-tank] weapons."
"We are about 600 Free Syrians fighting in Salaheddine and it is not enough," he said.
The violence has displaced 1.5-million people inside Syria and forced many to flee abroad, with 150 000 registered refugees in Turkey, Jordan, Lebanon and Iraq, UN figures show.
UN emergency relief coordinator Valerie Amos visited on Tuesday to discuss aid for civilians trapped or uprooted by the fighting, which has frequently prevented the delivery of food and medical supplies.
"She's there to express her grave, grave concern over the situation," spokesperson Jens Laerke said. "She will look at the situation on the ground and discuss with the government and humanitarian partners how to scale up the response in Syria." – © Guardian News and Media 2012, Reuters