Two suspected terrorist have been killed and 16 others arrested during armed clashes with security forces in Tunis.
Weapons including grenades and rifles were recovered in the raid, which happened in the Mnihla district.
The Interior Ministry said the group was planning sychronised attacks on the capital.
The raid follows two terror attacks against western tourists in Tunisia last year, one at the Bardo museum in Tunis and another at a beach resort in Sousse in which 36 people were killed, 30 of them British.
The Foreign Office has been advising against all but essential travel to Tunisia since the beach massacre last June.
Last month, Andrew Murrison, recently appointed by David Cameron as Trade Envoy to Tunisia and Morocco, visited Tunis to meet with officials and business leaders and told them tourism ties would be resumed as soon as possible.
