Tunisian police killed a Salafist Muslim after a group of assailants attacked a police station in the northeastern town of Hergla, the interior ministry and media reports said on Friday.

During the incident on Thursday night, police fired tear gas and warning shots to disperse a group of Salafists seeking to free one of their number being held there, private radio station Mosaique FM reported.

The 23-year-old was mortally wounded in the clashes, which continued into Friday morning, and four others were wounded.

The interior ministry said on its official Facebook page that 150 radical Islamists tried to break in to the police station, throwing rocks at security forces.

"To start, the police gave them a verbal warning, before firing tear gas to disperse them. The group persisted, so security forces were ordered to use live rounds, killing one attacker and wounding four others," the statement said.

Since the revolution that toppled the regime of Zine el Abidine Ben Ali in 2011, radical Islamists have launched several attacks on police stations across Tunisia.

Tunisia is facing a growing number of Islamist groups that authorities say are responsible for incidents such as the attack on the US embassy in Tunis in September and opposition politician Chokri Belaid's assassination in February.