A 15-year-old student has lost his hand after a stun grenade exploded during ongoing school protests in the northern French city of Lens, authorities and local media have reported.

The incident occurred on Monday, October 5, as demonstrations over deteriorating school conditions, teacher shortages and overcrowded classrooms continued across France.

Local prefect François-Xavier Lauch confirmed that the teenager suffered the serious injury in Lens and said an investigation had been opened into the circumstances surrounding the incident.

According to the local newspaper La Voix du Nord, the teenager picked up a police stun grenade during the confrontation before it exploded in his hand. Reuters subsequently clarified that this detail was attributed to the newspaper and was not directly confirmed by the prefect.

The incident has intensified scrutiny of the increasingly tense confrontations between student protesters and police as the demonstrations enter their third week.

The protests began in late September at a high school in the Paris region over teacher shortages before spreading to cities across France. Students have raised concerns about overcrowded classrooms, long school hours, inadequate staffing and deteriorating school buildings.

By Monday, between 400 and 500 of France’s roughly 3,700 high schools were expected to be fully or partially closed, according to Education Minister Edouard Geffray.

The Education Ministry also reported that 24 schools had been burned or ransacked and 78 education workers had been injured since the protests began.

The unrest has also produced clashes between police and demonstrators in several cities. Tear gas was reportedly used in Toulouse, while confrontations were reported in Lille and other locations.

The French government has acknowledged some of the students’ grievances. Prime Minister Sébastien Lecornu has instructed ministers to address demands including the replacement of absent teachers, school infrastructure repairs and concerns over lengthy school days.

Student organisations, meanwhile, have called for a nationwide day of demonstrations, with teachers, trade unions and parents expected to participate in solidarity actions.

The injury in Lens comes amid growing criticism from some unions and protesters over the policing of the demonstrations. Sophie Binet, secretary-general of the CGT trade union, criticised what she described as an excessive police response and called for the government to address the underlying problems in the education system.

Authorities are continuing to investigate the circumstances of the Lens incident. At present, the confirmed fact is that the 15-year-old suffered the loss of his hand during the protest; the precise sequence of events involving the police grenade remains part of the investigation.