A teacher at a school in southwest France was killed on Wednesday in a stabbing attack by a teenage pupil in the middle of a lesson, the regional prosecutor said.

The teacher of Spanish, 52, was teaching a class at the school in the seaside town of Saint-Jean-de-Luz when the pupil, 16, attacked her with a knife.

She was given emergency aid at the scene, but Bayonne prosecutor Jerome Bourrier told AFP she died of her wounds. He added that the pupil was arrested.

The local daily Sud Ouest said the boy stormed into the teacher's Spanish class with a knife and attacked her.

The school, Saint-Thomas d'Aquin, is a private and Catholic-based establishment close to the centre of Saint-Jean-de-Luz, which in summer is one of France's best-loved resorts on the sandy Basque country coast.

By lunchtime, pupils were gradually leaving the premises after being confined to their classrooms for around two hours after the stabbing.

Anxious parents were waiting for them but only those parents of the class where the stabbing happened were allowed to enter the school, an AFP reporter said.

- 'Trauma for nation' -

France's Education Minister Pap Ndiaye said he was "extremely upset" by the death of the teacher and would be heading to the scene.

"I can barely imagine the trauma that this represents at a local level and more generally on a national scale," said government spokesman Olivier Veran.

The BFM television channel said that the attacker had locked the classroom door and stabbed the teacher in her chest.

The channel quoted a source as saying that the boy then told another teacher that a "voice" had told him to carry out the action.

He is now in police custody, it said. No details have been released concerning his background.

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.

In July 2014, a 34-year-old teacher was stabbed to death in the southern town of Albi by the mother of a pupil. The perpetrator was later found to be legally irresponsible.

A Jewish school was targeted in the attacks carried out by Islamist gunman Mohamed Merah around Toulouse in 2012, with a teacher and three pupils shot dead.