The government said the curfew was necessary because of 'disturbances, pillaging and attacks' [EPA]

A dusk-to-dawn curfew has been called in Tunisia's capital after rioters demanding action on food prices and unemployment brought their protests to the heart of the city.

The army deployed armoured vehices around Tunis on Wednesday as the government sought to put a lid on the unrest which has left at least 20 people dead across the country.

The Tunisian president sacked Rafik Belhaj Kacem, his interior minister, on Wednesday after he was widely criticised for its ruthless response to the protests.

However, the measures did little to immediately calm the situation as hundreds of protesters hurled stones at police at a key intersection in Tunis. Officers responded with volleys of tear gas, driving the protesters to disperse into adjoining streets. Stores in the area were shuttered.

It was not immediately clear whether there were any injuries or arrests. Two army vehicles were posted at the intersection, which is close to the French embassy.

In another neighbourhood in central Tunis, hundreds of protesters tried to reach the regional governor's office but were blocked by riot police. And at the main national union headquarters, police surrounded protesters who tried to break out. Tensions also erupted along the edges of the capital.

'Pillaging and atacks'

The interior ministry ordered the curfew from 8pm (1900 GMT) to 5:30am on Thursday, citing "disturbances, pillaging and attacks against people and property which have occurred in some districts of the city".

Tunis had been spared the protests that began in mid-December, and turned violent in the west of the country at the weekend when security forces opened fire on demonstrators, until Tuesday when rioters attacked a local goverment office in the Cite Ettadhamen quarter.  

Read more about Tunisia's unrest on the spotlight page

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.

Meanwhile, sources told Al Jazeera that five people had been killed in fresh clashes between protesters and security forces in the south.

Mohamed Ghannouchi, the prime minister, told a news conference on Wednesday that all those arrested in the wave of demonstrations had been released, but gave no figure for how many had been originally detained.

Zine al-Abidine Ben Ali, the president, had only a few days earlier accused the rioters of committing acts of "terrorism".

Ghannouchi also said that allegations by opposition and non-government groups into corruption would be investigated by a special commission.

Ayesha Sabavala, a Tunisia analyst is with the Economist Intelligence Unit, told Al Jazeera that the government's measures were significant.

"The government is trying to tell people that 'we know we have made mistakes and we know there is widespread discontent, we are trying to address theses issues'," she told Al Jazeera from London.

"But the president himself, in his speech on January 10, promised the creation of 300,000 jobs in the next two years, which in my opinion is highly ambitious given Tunisia growth rate."

Serious changes

Radwan Masmoudi, an expert on Tunisia, told Al Jazeera that the president's change in direction is a beginning, but people's demands are for greater reform and genuine democracy.

"I think it has finally dawned on the president that these demands are not going to go away," Masmoudi said.

"He realises he has to make some serious changes and not just of people but in policies.

"People see corruption as the main problem in Tunisia so there is a tie between economic development and political institutions to guard against corruption."

Also on Wednesday, the European Union condemned the "disproportionate" use of force by police against demonstrators during the deadly protests.

Catherine Ashton, a spokeswoman for EU foreign policy chief, said the violence in Tunisia was "unacceptable" and that those responsible "must be identified and brought to justice".

The rare unrest in tightly controlled Tunisia was unleashed by the suicide of a 26-year-old man who set himself on fire on December 17 after police prevented him from selling fruit and vegetables to make a living.

Source: Al Jazeera and agencies