Incident in Kasserine region comes as campaign for September 15 presidential election officially opens.

A Tunisian security chief and three fighters have been killed in an exchange of fire near the border with Algeria, according to officials.

The incident in Hidra town in the Kasserine region came as campaigning for Tunisia’s presidential elections on September 15 officially opened on Monday following the death of the country’s first democratically elected president, 92-year-old Beji Caid Essebsi, in July.

State news agency TAP cited a statement by the interior ministry as saying that “three terrorists” were killed in an operation involving National Guard and army units.

Lieutenant Nejib Allah Cherni, chief of Hidra National Guard district, was also killed in the exchange of fire, it added.

Radio Mosaique reported that Tunisian National Guard officers opened fire on an armed group whose fighters were trying to cross the region of Kasserine from the Kef mountains.

Citing local sources, the report said the security operation was ongoing near the town of Hidra.

Tunisia has been battling armed groups operating in remote areas near the border with Algeria since an uprising overthrew former president Zine El Abidine Ben Ali in 2011. High unemployment has also stoked unrest in recent years.

The country has also been hit by a spate of attacks claimed by the Islamic State of Iraq and the Levant (ISIL, or ISIS) and al-Qaeda armed groups in recent years, killing dozens of security personnel and foreign tourists.

Last October, a woman blew herself up in the centre of Tunis, wounding 15 people, including 10 police officers, in an explosion that broke a long period of calm after dozens had died in attacks in 2015.