A Tunisian colonel and two foreign militants were killed Wednesday during a clash near the Algerian border, the Interior Ministry said.
The attack in Rouhia, in the center-west region of Siliana, was the fourth time in less than a week that Tunisian security forces have uncovered foreign fighters from neighboring countries in North Africa.
A third fighter fled, firing an assault rifle at a helicopter, officials said. The official TAP news agency quoted local residents as saying the three were wearing explosive belts.
Two other soldiers were wounded, one of them seriously, during the clash about 80 miles (130 kilometers) from the border with Algeria, Tunisia's western neighbor.
The TAP news agency quoted the ministry as saying that the group of three attackers were foreigners from Maghreb countries like Tunisia. It was not immediately known whether they were members of al-Qaida in the Islamic Maghreb, an Algeria-based offshoot known as AQIM.
On Tuesday, two Libyans were arrested in Medenine, near the Libyan border, and they admitted belonging to AQIM, Interior Ministry spokesman Neji Zairi told The Associated Press. The two said they had been in Tunisia for two weeks, Zairi said.
Tensions have flared on the border in recent weeks as fighting in Libya has spilled over into Tunisia, which is struggling to restore stability after an uprising earlier this year that sparked revolts around the Arab world. But Tunisian officials have not said whether the chaos in Libya is providing an opening for terror cells to cross borders and perhaps set up a base or traffic in weapons.
According to private Radio Mosaique FM, one of the largest stations in Tunisia, the group in Wednesday's attack was made up of nine people _ three Algerians, three Libyans and three Tunisians. The radio station suggested they belonged to AQIM. That report could not immediately be confirmed.
Tunisian security forces patrolled the mountainous area in search of other suspects, TAP said.
Tunisian security forces have been active on the eastern border with Libya, where fighting between rebels and forces of Libyan leader Moammar Gadhafi have been spilling into Tunisia.
But security forces have also arrested two suspected militants in the Libyan border region and uncovered arms caches.
Two other people suspected of links to al-Qaida's North African affiliate were arrested early Sunday, one with a belt of explosives and the other carrying a grenade, Tunisian state television has reported. They were arrested in the mountains outside Remada, a town in the Libyan border region. TAP said one was Libyan and the other Algerian. Interrogations led security forces to caches of weapons and explosives.
AQIM, formed at the end of 2006, remains active in its Algerian base, recently striking mainly security forces, while its southern branch in the vast desert region south of Algeria holds four French hostages taken captive in September in Niger.