Tunisian forces repelled a terrorist assault Monday on a town near the Libyan border, killing 35 gunmen in what authorities said was a thwarted effort to establish an emirate of ISIL

Tunisian forces repelled a terrorist assault Monday on a town near the Libyan border, killing 35 gunmen in what authorities said was a thwarted effort to establish an emirate of the so-called 'Islamic State of Iraq and the Levant' (ISIL) takfiri group.

Among a total of more than 50 dead, 11 members of the security forces and seven civilians were killed in the fighting in Ben Guerdane that President Beji Caid Essebsi condemned as an "unprecedented" attack.

It prompted authorities to close the frontier and order a nighttime curfew.

Prime Minister Habib Essid, using an Arabic acronym for ISIL group, said the aim of the operation had been to set up a "Daesh emirate" in Ben Guerdane, but the army and internal security forces had thwarted the attackers.

For his part, Essebsi, in an earlier statement broadcast on state television, said the assault was "maybe aimed at controlling" the border region with Libya, and he vowed to "exterminate these rats".

Residents of the border town told AFP the assailants had stopped residents, checked their IDs apparently to seek out members of the security forces, and announced their brief takeover of the town as "liberators".

It was the second deadly clash in the border area in less than a week as Tunisia battles to prevent the large number of its nationals who have joined ISIL in Libya from returning to carry out attacks at home.

The government said that an army barracks and police and National Guard posts in Ben Guerdane came under attack in coordinated pre-dawn assaults.

The defense ministry said at least 35 militants, six members of the National Guard, two policemen, a customs official and a soldier died in the fighting.

Seven civilians were also killed, and seven militants were captured, the defense ministry added.

Hospital official Abdelkrim Chafroud said a 12-year-old boy was among the dead civilians.

An AFP correspondent reported that schools and offices in Ben Guerdane were closed and troops were posted on rooftops across town as helicopters hovered overhead.

The militants have taken advantage of a power vacuum since the NATO-backed overthrow of longtime dictator Moammar Gaddafi in 2011 to set up bases in several areas of Libya, including the Sabratha area between Tripoli and the Tunisian border.