Squads of men shot at random from cars in Tunis on Saturday and inmates staged a mass jailbreak as leaders sought to map out Tunisia's political future after the president was swept from power.

It was not clear who the assailants were but a senior military source told Reuters that people affiliated to former President Zine al-Abidine Ben Ali were behind the attacks.

Soldiers and tanks were stationed in the centre of Tunis to try to restore order after a night of looting after Ben Ali fled to Saudi Arabia following a month of violent anti-government protests that claimed dozens of lives.

 The speaker of Tunisia's parliament, Fouad Mebazza, was sworn in as interim president, the official TAP news agency said. He has asked Prime Minister Mohamed Ghannouchi to form a coalition government.

Tunisia's highest legal authority on constitutional issues said a presidential election should be held within 60 days.

In a sign that Ben Ali's rule was over, workers were taking down a portrait of the former president outside the headquarters of his RCD party on Mohamed V Avenue in the centre of Tunis.

'We are very happy to be free after 23 years of prison,' said Fahmi Bouraoui, who was drinking coffee in the Mozart cafe, one of a few businesses that re-opened on Saturday morning.

But his optimism could be short-lived as parts of the country descended in to chaos.

Tunisian analyst Taoufik Ayachi said of the drive-by shootings, about 10 km from the city centre on Saturday and in another suburb on Friday night: 'It is certain the presidential police are behind all this. They still hope to regain power.'

Dozens of inmates were killed when they broke out of Mahdia prison and the prison at Monastir, also south of the capital, was on fire after a separate escape attempt, witnesses said.

'They tried to escape and the police fired on them. Now there are tens of people dead and everybody has escaped,' said a local man, Imed, who lives 200 metres from Mahdia jail.

Forty-two people died in the Monastir break-out, the official news agency said.

In suburban Tunis, the big Geant shopping centre was on fire, witnesses said. Protesters have threatened to continue their campaign against poverty and repression until the government is gone.

'We will be back on the streets, in Martyrs Square, to continue this civil disobedience until the regime is gone. The street has spoken,' said Fadhel Bel Taher, whose brother was one of dozens of people killed in the protests.

The Eurasia Group consultancy said that without a definitive timetable for elections or a transitional government, protests could continue: 'Although the streets of Tunis are calmer than they have been in several days, Ben Ali's departure is not likely to immediately defuse tension across the country.'

The acting president on state television he had asked the prime minister to form a coalition government.'I have called on Mohamed Ghannouchi to form a new government of national unity,' Mebazza, the speaker of parliament who was sworn in as interim president, said in televised comments.

An opposition leader who had talks with the prime minister on Saturday over a possible coalition told Reuters more talks would be held on Sunday.

'We discussed the idea of a coalition government and the prime minister accepted our request to have a coalition government,' Mustafa Ben Jaafar, leader of the Union of Freedom and Labour party, told Reuters. 
  
'Tomorrow there will be another meeting with the aim of getting the country out of this situation and to have real reforms. The results of these discussions will be announced tomorrow.'

The violence and fall of Ben Ali sent shockwaves across the Arab world where authoritarian rulers who face pressure from young populations disenchanted with their repressive policies and lack of economic prospects.-Reuters