At least five people suffered gunshot wounds in clashes with police in the centre of Tunisia's capital on Wednesday in a sharp escalation of the worst unrest in decades.
In the Lafayette district of the capital, the city's main shopping area, gunshots rang out and I saw two civilians fall to the ground injured while three others ran from the scene with bloody wounds to their legs.
Nearby, black smoke billowed into the sky as people covered their mouths against the fumes and police blocked off the area, while more gunshots rang out.
There was a protest and police used tear gas and gunfire to disperse the crowds, said a witness in a nearby street.
The unrest, in its fourth week, had been confined to provincial towns and working class suburbs on the outskirts of the capital.
On Thursday all shops in Tunis city centre were closed with their shutters down and armed soldiers, brought in to reinforce the police, stood guard outside government buildings behind banks of razor wire.
The protesters say they are angry about unemployment, corruption and what they say is government repression. Officials say the protests have been hijacked by a minority of violent extremists who want to undermine Tunisia.
France, the former colonial ruler and a close Tunisian ally, implicitly criticised the government's handling of the protests.
We insist that all parties show restraint and choose the path of dialogue ... we cannot continue with this disproportionate use of violence, Prime Minister Francois Fillon said on an official visit to London.
State television said President Zine al-Abidine Ben Ali, facing the biggest challenge to his rule since he took office in 1987, would make an address later in the day.
The latest official count for the number of civilians killed in the unrest is 23. But witnesses told Reuters on Wednesday another five had been killed, while the United Nations said rights groups put the toll at almost 40.
U.N. High Commissioner for Human Rights Navi Pillay said the deaths were a result of some excessive measures used, such as snipers (and) the indiscriminate killing of peaceful protesters.
The government says police have only fired in self-defence when rioters attacked with petrol bombs and sticks. It also says death tolls from rights groups are inflated.
On Wednesday Ben Ali sacked his interior minister and ordered the release of arrested rioters but people taking part in the clashes said that was not enough to meet their demands.
The government ordered the suspension of all sports events for the week, official media reported.
A nightly curfew for Tunis and suburbs was introduced at 8 p.m. (7:00 p.m. British time) on Wednesday.
But for several hours after that, crowds in at least two neighbourhoods of the city threw stones at police and ransacked buildings, Reuters reporters at the scene and witnesses said.
A resident of the working class Ettadamen suburb, 25-year-old Mejdi Nasri, was shot in the head by a stray bullet as he tried to reach his home, members of his family said.
It was the first time since the wave of unrest broke out that anyone had been killed in the capital. Asked to confirm the death, officials said they could not immediately comment.
A Reuters reporter said crowds angered by the killing later gathered in the suburb. Shots could be heard and a police helicopter was flying overhead.
In the provincial town of Sidi Bouzid, several witnesses told Reuters by telephone that between 7,000 and 10,000 people were marching through the streets.
Asked what slogans the crowd were shouting, one witness, who did not want to be named, told Reuters: It is not just about unemployment any more. It's about freedom of expression, freedom of assembly, all the freedoms.
Some analysts say the Tunisian government is likely to be able to contain the unrest, but that in the longer term Ben Ali could find himself weakened and his opponents emboldened.
The protests are being watched closely in other countries in the Arab world with the potential for social unrest, especially after rises in world food prices.
Tourism, which accounted for 11 percent of Tunisia's hard currency earnings last year, may become vulnerable. On Thursday the Netherlands issued a statement advising against all non-essential travel to Tunisia.
One of the region's most open economies, the country has been attracting steady interest from foreign investors.
The main Tunis stock market index fell 3.78 percent on Thursday, the fourth day of losses, taking it to a 12-month low. Credit default swaps -- or the cost of insuring exposure to Tunisian risk -- reached 18-month highs.