Troops deployed in the Tunisian capital Wednesday as the government sacked the interior minister and announced it would free detained protestors after weeks of demonstrations that unions said left scores dead.
In a sign of increasing government concern, armoured vehicles rumbled through Tunis and troops took up positions at major intersections and the entrance to the Cite Ettadhamen quarter where rioters burnt vehicles and attacked government offices late Tuesday.
It was the first rioting in the capital since protests over unemployment erupted mid-December, turning violent in the west of the country at the weekend when security forces opened fire on demonstrators.
With the government criticised for using excessive force against demonstrators, Prime Minister Mohamed Ghannouchi announced the dismissal of interior minister Rafik Belhaj Kacem, responsible for the police force.
The government said 21 people were killed in three days of unrest in the western Kasserine region, and that security forces acted in self-defence, but labour unions and rights groups said more than 50 were killed.
Ghannouchi also told a press conference that all those arrested in the wave of demonstrations had been released, but gave no figure for how many had been originally detained.
Opposition sources said army chief General Rachid Ammar was also sacked for refusing to order soldiers to stop rioters, but this was not confirmed by official sources.
The prime minister also said allegations by opposition and non-government groups into corruption would be investigated by a special commission.
"We have decided on the creation of a commission of investigation to look into the question of corruption," he told reporters.
Troops deploying in Tunis took up positions around the headquarters of the state broadcaster and a central tramway station.
Extra police and special intervention units also stood guard in a central square, across from the French embassy and the main cathedral, where on Tuesday police had dispersed demonstrators who were gathering to condemn the deadly crackdown.
Violence broke out later Tuesday in Cite Ettadhamen, several kilometres from the centre of the capital. Young protesters burned vehicles and looted businesses, some of them shouting "We are not afraid!", witnesses said.
Police fired tear gas at the protesters and shots could be heard, the witnesses said.
Charred vehicles and smouldering tyres remained in the area early Wednesday, an AFP reporter said.
The European Union raised concern about the "disproportionate" use of force against the protesters, echoing concerns raised late Tuesday by the United States.
The violence was "unacceptable" and those responsible "must be identified and brought to justice", a spokeswoman for EU foreign policy chief Catherine Ashton said.
"We are concerned about the disproportionate use of force by police against peaceful demonstrators," spokeswoman Maja Kocijancic said.
The United States said Tuesday it was "deeply concerned by reports of the use of excessive force by the government of Tunisia".
Protesters unleashed a rare wave of protests in the tightly controlled north African country following the suicide of a 26-year-old graduate who set himself on fire on 17 December after police prevented him from selling fruit and vegetables at a market.
In a bid to quell the protests, President Zine Al-Abidine Ben Ali announced Monday the creation of 300,000 jobs on top of 50,000 already pledged for the regions, but branded the protesters "gangs of thugs".
Tunisia's unemployment rate is officially 14 per cent, but the percentage of graduates without work is about double that.