More than 8,000 secular demonstrators gathered outside the Interior Ministry in Tunis's Bourguiba Avenue, the same spot where mass protests forced veteran leader Ben Ali to accept his rule was over and flee the country on Jan. 14, 2011.

Protesters filled the central boulevard, carrying banners that read "No fear, no horror, power belongs to the people" and "No to emerging dictatorship No to religious dictatorship".

The moderate Islamist Ennahda party won elections in October 2011, but has struggled to restore security and stability.

"Ennahda out, down with the (Muslim) Brotherhood Party," chanted the demonstrators, waving red and white Tunisian flags. "Where is the constitution? Where is democracy?"

Tunisians rose up against Ben Ali after street peddler Mohamed Bouazizi set fire to himself in despair at the confiscation of his fruit cart in the town of Sidi Bouzid.

Popular unrest then convulsed much of the Arab world, ousting or challenging entrenched rulers in Egypt, Libya, Yemen, Bahrain and Syria, which is still mired in a civil war that the United Nations says has cost more than 60,000 lives.