Tunisian troops have captured a large arms cache near the border with Libya, including Kalashnikov rifles, rockets and landmines, the government said.
Tunisia is waging a campaign against hardline Islamist groups who emerged after a 2011 uprising against autocrat Zine El-Abidine Ben Ali that put the North African country on track to democracy.
"A large number of Kalashnikov assault rifles, rocket-propelled grenades, and explosives were seized in the southern city of Ben Guerdan," Interior Ministry spokesman Mohamed Ali Aroui said. The raid was on Thursday night.
Tunisia is worried that violence will spill over from neighbouring Libya, where Islamic State has expanded, exploiting widespread turmoil as two rival governments battle for control.
At least two Islamist militant groups operate in Tunisia, and analysts say Islamic State is also seeking to spread its influence across the region.
Tunisian police this week killed two Islamist militants during clashes near the Algerian border, where the military has been targeted previously in ambushes.
Among the militant groups that emerged after 2011 is Ansar al-Sharia, which is listed as a terrorist organisation by US and European officials after being blamed for a 2012 storming of the US embassy in Tunis.
More than 3,000 Tunisians have also left to join militants fighting in Syria and Iraq, and the government is concerned about the prospect of returning jihadi fighters carrying out attacks on their home soil.