TUNIS, Tunisia (AP) — Extremist gunmen in search of food battled Tunisian security forces at a construction site and attacked a house in a third day of fighting near the Libyan border, the government said.

A manhunt in a 20-kilometer (12-mile) perimeter around Ben Guerdane has closed access roads as security forces search for armed men who fled the fighting that began Monday at dawn.

A total of 46 fighters have been reported killed since Monday in an operation that officials say can continue for days as security forces track assailants to safe houses.

On Wednesday, two gunmen who raided a construction site looking for food died in a battle with security forces, while two others who attacked a house in search of something to eat escaped. Another suspect barricaded inside a house died in a gunbattle.

No group immediately claimed responsibility for the violence in a region near lawless Libya where the Islamic State group has a growing presence.

A dozen members of the security forces and seven civilians have been killed since Monday.

Information from seven arrested attackers led security forces to arms depots, authorities said.

Prime Minister Habib Essid said on Tuesday that some 50 people took part in the attack, most of them Tunisians. Not all bodies have yet been identified.

"We know that the monitoring, verifying, and follow-up operations require time, maybe days," said Khaled Chouket, the Tunisian government spokesman. Chouket said the government investigation was trying to determine if there were extremist sleeper cells made up of residents who knew the area well enough to carry out surveillance on the head of the town's anti-terror brigade, who was killed as he left for work.

Websites affiliated with IS said militants were handed a tough blow by Tunisian security forces.

Tunisia has been a model of relative stability for the region since an uprising five years ago ushered in the democratic process and inspired Arab Spring protests against dictatorships across the region.

The Tunisian prime minister said on Tuesday that the goal of the attackers was to set up an "emirate of Daesh," another name for the Islamic State group.

French Foreign Minister Jean-Marc Ayrault, in Cairo on Wednesday, called for a Libyan political deal and a U.N.-backed unity government as a way to combat IS.

"The Islamic State is expanding in North Africa, because of the Libyan divisions," Ayrault said.