France has suspended police use of stun grenades at high-school protests after a 15-year-old lost his hand in Lens on Monday, Interior Minister Laurent Nunez announced early Wednesday.

Nunez said there is a “strong possibility” a stun grenade caused the teenager’s injury. Eighteen misconduct cases have been referred to the police inspectorate, and a separate officer was charged after a 14-year-old near Paris lost teeth when struck in the face by a tear gas grenade fired at close range.

The suspension follows a massive day of demonstrations Tuesday, when more than 260,000 people marched across France over crumbling schools, teacher shortages and overcrowded classrooms. Police made 488 arrests that day, and 24 high schools were damaged or shut.

Prime Minister Sébastien Lecornu is addressing the nation Wednesday evening, with fresh coordinated protests planned for Thursday.