Paris: Tunisia's defence minister estimated Tuesday that some 1,000 of his countrymen are fighting for the Islamic State group in Libya, branding them a threat to their home nation.

On the sidelines of a security conference in Paris, Farhat Horchani told journalists that reports of 2,000-3,000 Tunisian jihadists in Libya are exaggerated, saying "it's on the order of 1,000."

For now the Tunisian fighters have not returned home in large numbers, but Horchani said "we must remain vigilant" as they remain a "threat", noting that some of them are dual French nationals.

He went on to say there is no regional plan to deal with foreign fighters in Libya, noting: "Countries handle the issue day-by-day".

"The war against terrorism is an all encompassing one. If we confront terrorism only on the security or military fronts, we lose the war," Horchani added.

"We must instill in young people that Islam is not this... If not, within a couple years we will have a monster more dangerous than Daesh," he said, using an Arabic acronym for IS.

The capture of the coastal Libyan city of Sirte by IS last year sparked fears the jihadists would use it as a springboard for attacks on Europe.

The Sunni extremists took advantage of the chaos in oil-rich Libya following the 2011 uprising, seizing the city in June 2015.

But forces loyal to Libya's Government of National Accord (GNA), backed by US airstrikes, have recaptured nearly all of Sirte, the jihadists' main stronghold in North Africa.

Horchani said he believed that among the fighters flushed this month from Sirte, "it is very probably that some went towards the south, and some will go towards the west".