France has suspended the use of stun grenades for policing student protests that have swept the country, after a 15-year-old’s hand was blown off earlier this week, the BBC reported.

Interior Minister Laurent Nuñez said he had requested the pause until the facts of Monday’s incident in Lens had been “clarified”, with conflicting accounts offered by protesters and officials.

Several groups have complained of police using disproportionate force towards teenagers.

The disruption continued on Wednesday with more than 500 schools fully or partially shut, and Prime Minister Sébastien Lecornu is due to speak about the school protests in an evening address.

Hundreds of thousands of people took to the streets on Tuesday to call for better school conditions and in some cities tear gas and water cannon were deployed. The interior ministry said 488 people were arrested and 43 members of the security forces were hurt.

Nuñez told French radio RTL that police watchdog IGPN had opened 18 investigations to determine whether officers had been “proportionate” during the demonstrations, which have spread from high school pupils to their parents, university students and unions.

“There is a police action that raises questions for all of us within the Ministry of the Interior; it’s what happened in Lens,” he said, and confirmed the use of stun grenades was being suspended “until the facts surrounding this case have been clarified”.

The 15-year-old boy’s hand was torn off after a so-called anti-encirclement grenade was fired in unclear circumstances near the Auguste Béhal high school in the northern city near Lille.

Authorities have said he picked up the grenade which then exploded, but students have alleged he was hit directly after an officer fired.

According to the local prefect, the incident took place when police were confronted by a group of 200-250 students throwing stones and fireworks.