Tunisian troops exchanged fire with militants near the Algerian border on Thursday night, a resident said, three days after gunmen killed eight soldiers in one of the deadliest attacks in decades on the country's security forces.
Soldiers had been doing security sweeps since Monday in Mount Chaambi, a remote area where the army has been trying to track down Islamist militants since December last year.
A resident in the nearby town of Kasserine told Reuters by telephone he could hear heavy intermediate gunfire on the mountain.
A Tunisian security source confirmed the attack. There was no news yet of casualties.
The rise in instability comes at a period of political turmoil in Tunisia, which has seen large protests against the moderate Islamist-led government.
Earlier on Thursday, Algerian media said Algeria had boosted its military presence near the border in coordination with Tunisian security forces due to increased tensions in the area.