Tunisia's Interior Ministry spokesman says police have carried out a pair of counter-terror operations, capturing two suspected militants in the deep south and surrounding a home near the capital.

Mohammed Ali Aroui said Thursday that the men were planning attacks and one bystander was killed in the southern town of Kebili during the exchange of fire.

Police are currently surrounding a house in the Oued Ellil suburb of Tunis and have exchanged fire with those inside. Aroui said there were several injured but gave no further details.

Tunisia is set to hold parliamentary elections on Sunday to complete its democratic transition.

Authorities had warned that Islamist radicals seeking to overthrow the state would attempt to disrupt the elections.