Chanting protesters called for the departure of the government and Prime Minister Beji Caid Sebsi, whistling at black-clad riot police in central Tunis.
Police fired teargas to push the protesters into streets off the central Avenue Bourguiba.
Tunsia has struggled to restore stability since leader Zine al-Abidine Ben Ali was ousted earlier this year in a revolution which inspired uprisings across the Arab world.
"The police reaction is too extreme against the people. It`s true there are criminals among the protesters, but the reaction is still too cruel. It is a return to the days of Ben Ali," said Chaqib, a civil servant who did not want to give his family name.
Tension is growing in Tunisia in the countdown to a July election for an assembly that will draw up a new constitution.
A moderate Islamist group banned under Ben Ali is expected to do well, unsettling many in the country`s secular establishment.
The spark for the violent protests over the past few days was a warning from a former interior minister that there would be a coup d`etat if the Islamist group, Ennahda, won the vote.
Protesters fear the interim administration will renege on its commitment to guide Tunisia towards democracy after decades of autocratic rule under Ben Ali.
The authorities -- who reject any suggestion there will be a coup -- responded to the protests by imposing an overnight curfew starting on Saturday. They said it was to ensure the safety of citizens. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2011
