Thousands of police and soldiers clashed with demonstrators at the main religious centre in the central city of Kairouan after the Government banned the annual conference of the Salafist organisation Ansar al-Sharia.
One protester died and several were injured amid security checkpoints and patrols. Protesters threw stones at police, who fired tear gas in response.
Kairouan hospital reported that five civilians and four policemen were injured. The State news agency reported that a 27-year-old was killed and 11 policemen wounded.
Authorities had refused a permit for the conference, calling it a threat “to security and public order".
In Ettadamon, a suburb of the capital Tunis, police fired tear gas and shots into the air to disperse about 500 stone-throwing protesters, some of whom set fire to cars, lowered the Tunisian flag, and replaced it with a black Islamist banner.