A primary school teacher (34) has been stabbed to death by a pupil's mother as children watched, prosecutors in France say.

The incident happened this morning at a school in Albi, near Toulouse, in the south of France. The mother has been arrested.

Prosecutor Claude Derens described what had happened.

"This morning, a mother showed up with a knife and stabbed a 34-year-old teacher in front of her students, for reasons that will be determined by the investigation" Mr. Derens said.

"When I arrived at the scene they were trying to revive her. She was in cardiac arrest in her classroom".

President Francois Hollande has sent Education Minister Benoit Hamon has been sent to the Edouard Herriot school, which teaches 284 pupils between the ages of three and 11.

Mr. Hamon was described as "deeply shocked by this crime, which plunges the end of the school year into mourning".

A spokesman for the Minister continued "This tragedy confirms there is a need to fight against violence in and around schools, to protect schools, teachers and students".

A news conference is due to be held later.

France has become increasingly concerned about pupils' parents assaulting teachers, with a study released in April revealing that nearly half of primary school head teachers said they had been verbally or physically assaulted by parents.