The shootout happened at Mount Salloum near the town of Kasserine close to the border with Algeria, where jihadists operate, local media reported.
"There was an exchange of fire between soldiers and a group of terrorists in the Kasserine area," defense ministry spokesman Mohamed Zekri told AFP.
"There were wounded among the terrorists who fled," he said, adding that two soldiers were slightly wounded.
The most recent similar clash was in March when suspected jihadists opened fire on a national guard barracks in the city of Kairouan, some 150 kilometers east of Kasserine.
In March 2016, an assault on security positions in Ben Guerdane near the border with Libya killed 13 members of the security forces and seven civilians.
At least 55 jihadists were also killed and dozens arrested.
The authorities say they have made significant progress in the fight against "terrorism", with no attack on that scale having taken place since.
After the 2011 revolution, Tunisia saw a boom in jihadist groups which launched attacks that killed dozens of tourists -- notably at the seaside resort of Sousse and at the Bardo National Museum in the capital -- as well as security personnel.