Three people have been killed in clashes between hundreds of demonstrators and security forces in the Tunisian capital, authorities say.
Police used tear gas, batons and live ammunition to disperse demonstrators outside the interior ministry in Tunis.
Police and masked men in civilian clothes, armed with sticks, moved through streets looking for protesters.
The protest comes a day after police cleared huge crowds from the streets demanding the prime minister resign.
That was the biggest rally since President Zine al-Abidine Ben Ali fled after weeks of unrest.
The fighting went on for several hours on Saturday, as protesters tried to storm the interior ministry, right in the centre of Tunis, and police repeatedly repelled their attacks, says the BBC's Paul Moss in Tunis.
In a statement, the interior ministry said: "Three people died from the dozen who were wounded during clashes and were transferred to hospital for treatment... Several members of the security forces were wounded to different degrees," it said without giving a number.
The statement added more than 100 people were arrested on Saturday and almost 90 had been arrested on Friday.
That follows one reported death in Friday's clashes, during which police fired tear gas and warning shots to disperse demonstrators.
The stench of tear gas again filled the main shopping street in Tunis on Saturday, our correspondent said.
The trouble flared very suddenly - people out shopping found themselves caught up in the confrontation, women carrying heavy bags running for cover with handkerchiefs clutched to their mouths, he added.
Several members of the security forces ran into the lobby of a hotel, yelling at startled customers drinking coffee to return to their rooms or leave the hotel immediately, he said.
The interim government of PM Mohammed Ghannouchi, who had served under ousted President Ben Ali since 1999, has promised elections by mid-July.
Although Mr Ghannouchi has introduced some reforms and removed a number of controversial cabinet members, protesters remain angry that figures from Mr Ben Ali's authoritarian government remain in the interim cabinet.