The attack took place in the town of Ghardimaou, located in Jendouba Governorate, at 11:00 a.m. local time (10:00 GMT), the TAP state news agency reported.
The security forces in two vehicles were patrolling the border area when a grenade was thrown at one of the cars. Exchange of fire between the military and terrorists followed the blast.
Since the Tunisian Revolution in 2011, the country has faced a growing terrorist threat. Since 2014, Tunisia has been conducting operations against militants linked to al-Qaeda* terrorist group, seeking to root them out from a hideout in the Chaambi area near the Algerian border.
In 2015, Tunisia was shaken by two terrorist attacks, at the Tunis Bardo National Museum in March and at a beach resort in the town of Sousse in June, which together claimed the lives of over 60 civilians, mostly foreign tourists.
*al-Qaeda — a terrorist group, banned in Russia