A woman was killed and a man wounded in western Tunisia late on Saturday after soldiers opened fire on their car fearing they were armed, a defence ministry spokesman told AFP.

The army had earlier received information about a car carrying an "armed group" in the Kasserine region and had dispatched soldiers to find it, the spokesman, Belhassen Oueslati, said.

The Kasserine region is located at the foot of the Chaambi mountain, where the army has since 2012 been chasing jihadists wanted for attacks that have killed several dozens of soldiers and policemen.

The car carrying the two young people was "a little hidden" on the edge of a road at the foot of the Sammama mountain, the spokesman said.

When the military convoy passed, "the driver started the car" and drove it between the army's first vehicle and the one following it.

"They could have been undesired armed elements... a car crammed with explosives. So they (the soldiers) fired," he said, adding that the incident happened in a "zone closed for military operations".

It was not clear whether the driver's actions had been deliberate or if he had panicked and tried to get away, the spokesman said. "We will know from the investigation."

According to a medical source at the Kasserine hospital, the young woman suffered fatal wounds to the kidney, while the young man was injured in the shoulder.

At the end of August last year, the Tunisian police had killed two young women who were cousins, one of whom held German nationality, as they drove around Kasserine, after mistaking them for members of an armed group.