An explosion has hit a bus carrying presidential guards in Tunisia'scapital, Tunis, state TV reports.
At least six people had been killed, an interior ministry spokesman said, Reuters news agency reports.
The cause of the blast was not immediately clear.
Tunisia has been targeted by militants from the Islamic State group, who attacked the beach resort of Sousse in June, killing 39 people, mostly foreign tourists.
The latest explosion took place on the Mohamed V Avenue, one of the main roads in Tunis, the privately owned Radio Mosaique reports.