Tunisia's Interior Ministry says nine terrorist suspects have been killed in overnight security operations ahead of a national march to denounce extremist violence.

Ministry spokesman Ali Aroui said Sunday that security forces clashed with the suspects in the southwest region of Sidi Aich, near the Algerian border. He said several extremists were wounded in another clash in the northwest region of Kef.

The overnight security operations around the country came hours ahead of a march through the capital organized to show solidarity against terrorism, after an attack on a leading museum that left 24 dead and shook the nation's fragile democracy.

Several foreign officials are expected to attend. Most of those killed in the March 18 attack on the National Bardo Musum were foreign tourists. Two attackers were also killed.