TUNIS (Reuters) - Five people were killed in renewed clashes in Tunisia on Wednesday, witnesses said, and protesters fought with police in the capital in defiance of a curfew aimed at stemming the worst unrest in decades.
Facing his most serious challenge since he came to power more than 23 years ago, President Zine el-Abidine Ben Ali offered an olive branch by firing his interior minister and freeing jailed protesters. But the moves failed to halt the violence.
People taking part in the unrest 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.
Crowds of people gathered to protest in three provincial towns, witnesses said. In Gassrine, about 200 km (125 miles) from the capital, several thousand people chanted "Ben Ali, go away!."
In the Sahara desert town of Douz, three witnesses told Reuters at least four people had been killed when police opened fire, including one university professor.
Two witnesses told Reuters that police in the town of Thala, scene of fatal shootings at the weekend, fired teargas to try to disperse a crowd of people but when that had no effect they opened fire, killing 23-year-old Wajdi Sayhi.
The victim was deaf, said his brother, Ramzi.
"The police told him to go home but he heard nothing, and they fired toward him," he told Reuters by telephone. "They (the government) promised us and promised us and now they have promised us death," he said.
Officials did not respond to calls from Reuters seeking comment on the witness accounts about the killings. The government says police only fire in self-defense when violent rioters attack with petrol bombs and sticks.
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.
Adding to mounting international pressure on Tunisia over its handling of the protests, the European Union, Tunisia's biggest trading partner, said the violence was unacceptable.
"We cannot accept the disproportionate use of force by the police against peaceful demonstrators," Maja Kocijancic, spokeswoman for EU foreign affairs chief Catherine Ashton, said.
The protests, now entering their fourth week, are being watched closely in other countries in the Arab world with the potential for social unrest.
The government declared a nightly curfew for Tunis and surrounding suburbs from 8 p.m. (1900) until 6 a.m., saying it was in response to violence.
When the curfew fell in the El Omran neighborhood on the outskirts of the city, hundreds of youths who had been throwing stones at police carried on, a Reuters reporter at the scene.
He said police responded with tear gas and by firing into the air. The youths had earlier set fire to a bank branch.
The latest official death toll from the unrest -- which is now entering its fourth week -- is 23, though some international rights groups say the count is higher.
Earlier, in an attempt to take the momentum out of the unrest, Prime Minister Mohamed Ghannounchi said the president had decided to appoint Ahmed Friaa, an academic and former junior minister, as the new interior minister.
He did not give a reason for the change but he said the president "has announced the creation of a committee of investigation into corruption and to assess the mistakes of certain officials."
In further concessions, he said Ben Ali had decided to free everybody detained over for taking part in the riots and promised financial help to jobless graduates -- a group whose grievances have been a driving force behind the unrest.
Military Humvee jeeps and armed soldiers were patrolling at least two locations in the center of Tunis on Wednesday and most shops were shut. Most parts of the city, on the Mediterranean coast, appeared calm after the curfew fell.
The unrest has alarmed investors in Tunisia, one of the region's most developed economies. Shares on the Tunis stock exchange closed 3.4 percent down on Wednesday to reach their lowest level in 38 weeks.
Additional reporting by David Brunnstrom in Brussels; Editing by Angus MacSwan