Tunisia's prime minister appointed opposition figures to a new unity government on Monday, trying to establish political stability after violent street protests brought down the president last Friday.

Prime Minister Mohamed Ghannouchi also said the government was committed to releasing all political prisoners, and that anyone with great wealth or suspected of corruption would face investigation.

About 1,000 demonstrators took to the streets earlier in the day demanding that the ruling party of ousted President Zine al-Abidine Ben Ali give up power and some said they would not accept members of the Ben Ali government in the new coalition.

Security forces used water cannon and tear gas and fired shots in the air to disperse the protest, which ended peacefully.

The ministers of defence, interior, finance and foreign affairs will keep their jobs in the new government and opposition leaders including Najib Chebbi will have posts, the prime minister said.

Ghannouchi named Chebbi, founder of the Progressive Democratic Party (PDP) which opposed Ben Ali, as minister of regional development.

Opposition figures Ahmed Ibrahim and Mustafa Ben Jaafar will also have cabinet posts, Ghannouchi said.

We are committed to intensifying our efforts to re-establish calm and peace in the hearts of all Tunisians. Our priority is security, as well as political and economic reform, Ghannouchi told a news conference.

On the streets of the capital, ordinary Tunisians were sceptical.

Mohamed Mishrgi said: We do not trust this government because there are the same faces, like Ghannouchi, Morjane and particularly Friaa. He has changed nothing. It's as if Ben Ali's system is still there. It's for that reason that the demonstrations are continuing in Tunis. We want a new state with new people. Another passerby, Hosni Saidani, added: It is difficult to trust these people because they participated in Ben Ali's system but they did not have the courage to say to him 'stop.' So how can they make a change towards democracy? These people participated in the system of Ben Ali. It's true, the people do not want them in the new government but we cannot have a complete change, we need to go towards democracy step by step, said city resident Mohamed Bouzayin.

Speaker of parliament Fouad Mebazza, sworn in as interim president, had asked Ghannouchi to form a government of national unity, and constitutional authorities said a presidential election should be held within 60 days.

Moncef Marzouki, a professor of medicine who leads the CPR Tunisian opposition party in exile in France, told Reuters separately he would be a candidate in a presidential election.

SHOCKWAVES IN ARAB WORLD

Ben Ali's fall on Friday after weeks of violent street unrest sent shockwaves through the Arab world, where autocratic leaders preside over similarly repressive governments.

Ben Ali fled to Saudi Arabia amid a popular revolt against unemployment, corruption, poverty and repression in which at least 100 people died.

Leading Tunisian economist Moncef Cheikhrouhou said the central bank had told him that the former president's family had taken 1.5 tonnes of gold worth $66 million out of the country.

Militia men loyal to Ben Ali had tried to raid the central bank on Sunday to remove more gold but had been routed by the army, he told Reuters in an interview.

Overnight, shooting could be heard in parts of Tunis, following clashes between special forces and members of the former president's security detail on Sunday.

Residents reported seeing people in cars, on motorcycles and on foot firing shots apparently at random and then disappearing. People searched the roofs of their apartment blocks after reports that gunmen were firing on people below.

There are snipers on the roof. We don't know where. We are asking for immediate help from security forces, one caller to state television said.

Tanks and soldiers were stationed on the streets of Tunis, and the U.S. embassy said it would evacuate family members of its staff to Rabat on Tuesday.

UN Secretary-General Ban Ki-Moon called for the establishment of the rule of law in Tunisia, while the Arab League said Arab states should consider what lessons could be learned from the crisis.

There were long lines outside bakeries in Tunis on Monday morning as people started buying provisions after several days when shops were shut and most people stayed inside their houses.

Government offices were open for the first time since Thursday, though some employees said they would stay at home because they did not think travelling was safe.

Tunisia's crisis, which began when a man set himself on fire after police seized his vegetable cart, seemed to be prompting copycat burnings. Four men were reported to have set themselves ablaze in Algeria, one in Egypt and one in Mauritania.

The crisis also raised fears for the economies of neighbouring countries. The cost of insuring north African nations' debt against default rose sharply on Monday.

Egyptian stocks posted their biggest drop in seven months and the pound dipped to its weakest in almost six years on Monday as investors feared turmoil in Tunisia could spread.

The Tunis stock exchange was closed for Monday.

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