Dutch police have arrested a suspect following an online threat to shoot a teacher and students that prompted authorities to close all the high schools in the city of Leiden.
Hague police spokeswoman Yvette Verboon confirmed the arrest but would give no further details of the identity of the suspect.
Ms Verboon says police are "investigating his involvement" in the threat that was discovered yesterday.
Police announced the school closures last night, saying they do not want to take any risks while the person who posted the threat remains unknown.
Mayor Henri Lenferink told Dutch television "it could be a morbid joke" but authorities do not want to risk children's lives.
Shooting rampages are rare in the Netherlands, where gun ownership is tightly controlled.