Tunisia's prime minister has fired five leading security officials after three gunmen attacked a Tunis museum, killing 21 in the deadliest attack on tourists in Tunisia in 13 years, the government said Monday.

The ousted officials include the director of Tunisia's tourist police and the police chief for the neighborhood around the National Bardo Museum, government spokesman Mufdi Mseddi told The Associated Press.

The decision was made after the prime minister visited the neighborhood of the attack and noted security problems, the spokesman said. President Beji Caid Essebsi had also criticized security failings around last week's attack.

The Islamic State group claimed responsibility for attacking the museum, a trove of Roman mosaics and Tunisia's leading historical museum.

Several well-armed groups in neighboring and chaotic Libya have pledged allegiance to IS. Tunisia is also fighting extremists claiming allegiance to al-Qaida in its western mountains.

A Tunisian defense official said Monday one soldier was killed and three others wounded when a mine blew up their vehicle in a mountainous area known to be a refuge for al-Qaida linked Islamic radicals.

Lt. Col. Belhassen Oueslati, a Defense Ministry spokesman, said the incident occurred Sunday in a mountainous region near the Algerian border. Al-Qaida linked radicals have staged attacks against army and politicians in the area for the past two years.