A teacher has been stabbed to death and two others seriously injured after a knife-wielding assailant shouted “Allahu Akbar” as he attacked a school in northern France, it has been reported.

Police were called to City School Gambetta-Carnot, a secondary school in Arras, on Friday morning after reports that three people were stabbed. Police have arrested the suspect, named in reports as Mohammed Mogouchkov.

French literature teacher Dominique Bernard was killed while a sports teacher and a security guard were also injured. No pupils were hurt, a police source said.

According to BFMTV, the suspect is a 20-year-old former pupil at the school. Le Parisien reported he is of Chechen origin and was known to authorities after being placed on a terror watch list.

The suspect’s brother was arrested near another school but was found not to be in possession of a weapon, according to police sources cited by Le Parisien.