A landmine killed four Tunisian soldiers on Wednesday during an counter-terrorism operation in mountainous central Tunisia, the defence ministry said.

"Four soldiers who were part of a military unit tasked with carrying out a combing operation of Mount Mghila looking for terrorist elements were killed by a mine," ministry spokesman Mohamed Zekri told AFP.

The sweep was "part of the regular anti-terrorist operations carried out by military forces in the region," Zekri added.

Tunisia has seen a surge in radical Islam since veteran president Zine El Abidine Ben Ali was ousted in the country's 2011 revolution.

Dozens of members of the security forces have been killed since then in jihadist attacks.

The bloodiest single attack against the army was in July 2014, when 15 soldiers were killed on Mount Chaambi.

The security situation has greatly improved in recent years, but Tunisian forces continue to be targeted.