"It is a sad day for our education system. It is a sad day, of course, for this school. And the time for the investigation will come, the time for possible conclusions will come," Ndiaye said. "Today is a time for emotion. It is a time for solidarity. We are present here, in the company of the authorities: the Prefect, the Rector, and also the elected representatives. Finally, the whole nation is present here to express its sorrow and emotion."

The 16-year-old pupil reportedly entered a Spanish class mid-lesson, locked the classroom door and stabbed the teacher in the chest with a knife.

Prosecutors said the 52-year-old was given emergency aid at the scene but died of cardiac arrest.

The assailant is now in police custody. A top government official, speaking anonymously because he was not allowed to discuss the issue publicly, said the first pieces of information communicated by police suggested that the attacker has severe mental health issues.

French media reported that the student, born in 2007, said he heard voices telling him to kill the teacher.

Other reports said that the boy claimed to be "possessed". The investigation will seek to determine his psychological state and motives.

No details have been released concerning his background.

Government spokesman Olivier Veran, speaking after a weekly Cabinet meeting, expressed the government's support for the education community and said the event represents a trauma for the nation.

Such attacks at schools are generally rare in France but there have been growing concerns about the security of teachers.

In the past 40 years, there have been fewer than a dozen deadly attacks in schools.

The attack in Saint-Jean-de-Luz is the first killing of a teacher in France since the October 2020 beheading of Samuel Paty outside Paris by an Islamist radical.