A Tunisian Interior Ministry official has warned of a plan to attack sites in the capital with car bombs and other devices, according to a state news agency.
The television report on TAP said unidentified militants planned to attack "sensitive sites" in Tunis with car bombs and explosive belts.
It added that police had banned traffic on Bourguiba Avenue in the heart of downtown and nearby streets to prevent attacks. There are also increased police patrols and raids around the capital and its suburbs.
In March and June, gunmen attacked the national museum and a beach resort killing nearly 60 foreign tourists. The attacks were claimed by the so-called Islamic State group.
