A bomb in a car parked outside a police post in the port of Tunis on Saturday left a policeman injured, according to a witness and local media.
The blast occurred at 5:45 am (0445 GMT) in La Goulette in the northern outskirts of the Tunisian capital, the witness and the Express FM and Shems FM radio stations reported.
The bomb went off when the policeman approached a four-wheel drive vehicle parked in front of the post after garbage collectors noticed a suspicious object underneath it, the witness told AFP.
Residents told AFP that the sound of the bomb woke them up and many of them panicked.
A spokesman for the Interior Ministry confirmed the bombing and said there had been no casualties, Reuters reported.
The incident is the first known attack of its kind against a security vehicle in Tunisia.
The attack comes two days after the assassination of opposition leader Mohamed Brahmi which sparked violent protests and a general strike. One man was killed on Saturday after police broke up demonstrations using tear gas.
(With AFP and Reuters)