Interior Ministry communications director Ridha Kazdalli said on national television the curfew is temporary and would be lifted "as soon as the situation improves."
The official TAP news agency reported that under the curfew people are banned from the streets from 9 p.m. until 5 a.m. local time.
Tunisian police fired warning shots earlier in the day in three suburbs of the capital, Tunis, to disperse radical Islamist protesters after they set a security post ablaze and ransacked an art exhibit they called offensive to Islam.
The violent incidents were the latest in a series of protests by Islamist radicals. Seven police officers have been injured and 90 people arrested in unrest since Sunday in the suburbs, Interior Ministry spokesman Lotfi Hidouri said earlier in the day.
The latest violence focused on the art exhibit, but reflects larger tensions between secular movements and ultraconservative Muslims known as Salafis. Protesters overthrew a longtime secular dictator in January 2011, and Tunisians have since voted in a moderate Islamist government. Radical Islam, however, has flourished on the fringes amid newfound religious freedoms.
Late Sunday, hundreds of extremists destroyed artworks at another exhibit in the suburb of La Marsa. The
The next night, radical protesters set fire to a police post in the suburb and a security kiosk in another suburb, Kram. Police fired warning shots to disperse the protesters, witnesses said.
In the poor suburb of Sijoumi, Salafi protesters also set fire to a courthouse and a security vehicle and looted stores Sunday night, according to private radio station Mosaique FM.
In the face of mounting unrest, authorities have said police would have permission to use live bullets if need be.
The curfew was the first since the new government took office in November.