The state news agency reports that a group of armed men killed a Tunisian national guardsman near the Algerian border.
The four gunmen opened fire Monday on a guard patrol in the area of Dernaya in Tunisia's Kasserine province, wounding one guardsman who later died at a hospital.
The report said the men had infiltrated the country from Algeria and reinforcements have been sent to the area. The report did not specify the identity of the men, but local media described them as Islamists.
On Saturday, two Tunisians were arrested carrying explosives and automatic weapons, also near the Algerian border.
A branch of al-Qaida is active in Algeria and has occasionally crossed into Tunisia, where hardline Islamists are on the rise since the ousting of a secular dictator in 2011.