Jihadists being pursued by the army on Tunisia's border with Algeria are veterans of the Islamist rebellion in Mali, where France led an intervention to oust them in January, Interior Minister Lotfi Ben Jeddou said Wednesday.

"They came from Mali," the minister said during an open session in the national assembly, without giving more details on the militants.

"I would have liked this to be a closed session to be able to say more," he told MPs, who were grilling him about the hunt for the two fugitive Islamist groups.

Tunisia's army intensified its search a week ago for the jihadists hiding out in the remote border region, who are blamed for an attack on a border post in December that left a policeman dead.

The interior ministry admitted on Tuesday that the militants had links to Al-Qaeda in the Islamic Maghreb, heightening concerns about the security threat posed by Tunisia's increasingly assertive Muslim extremists.

Ben Jeddou did not say whether the Islamist fighters from Mali had joined jihadist groups in Tunisia before or after France's military intervention, which has raised fears of revenge attacks by Al-Qaeda's north Africa affiliate.

The devastating assault by Islamist gunmen on a desert gas plant in Algeria in January that left dozens of foreign hostages dead was linked to France's invasion of Mali. Algeria said 11 of the 32 assailants were Tunisian.

The two jihadist groups being hunted in Tunisia consist of around 30 people, according to the minister, the one located around Mount Chaambi being made up of 20 fighters, "half of them Tunisian and half Algerian."

The second smaller one is based in the Kef region further north.

The Chaambi group has been pursued since the deadly attack on the border post in December.

But the hunt was stepped up late last month, when bombs planted by the militants began causing injuries to the armed forces combing the area. So far, 16 soldiers and national guards have been wounded, some seriously.

In the past three days, two alleged accomplices of the jihadists have been arrested, bringing to 37 the number of suspects detained in the region since December, but the defence ministry says no combatants have yet been arrested or killed.

Defence Minister Rachid Sabbagh accepted that the search had been made harder by the army's lack of proper equipment, especially for detecting the homemade explosives that the militants had placed around Mount Chaambi.

"The demining operations have not produced great results... We will need to train sniffer dogs," he told parliament during the same session.

But he vowed that the army would remain in place "until the eradication" of the jihadists, while also welcoming Algeria's cooperation and exchange of information.

Earlier on Wednesday, Prime Minister Ali Larayedh insisted that the security situation in Tunisia was improving and that the fugitive jihadist groups would be defeated.

"We will pursue our confrontation with the violent terrorist groups... dismantle their structures and bring them to justice," said the former interior minister and stalwart of the ruling Islamist party Ennahda.

Opposition MPs strongly criticised Larayedh for failing to clamp down on radical Islamist groups during his tenure as interior minister between December 2011 and March 2013.

"We are heading towards civil war," said Hichem Hosni, an independent MP.

Samir Bettaieb, a lawmaker from the centrist Democratic Group, slammed the authorities' inability to take control of mosques that had fallen under the sway of the hardline Salafist movement.

"There is a lack of policy for controlling mosques ... The Chaambi terrorists can take refuge there," he said.

Since the revolution in January 2011 that ousted Zine El Abidine Ben Ali, Tunisia has seen a proliferation of radical Islamist groups that were suppressed under the former dictator.

Those groups have been blamed for a wave of violence, notably an attack on the US embassy last September and the assassination of a leftist opposition leader in February, cases which Ennahda has sought to portray as isolated incidents.