Police have arrested two teenagers from Dronten and Almere suspected of sending an e-mail containing “a serious threat” to a school in Almere.

The boys were located after an investigation by the police digital expertise team, and are being held for interrogation.

Police have not commented on their age or if they are pupils at the Ooostvaarderscollege.

Threats of violence to schools are no longer isolated incidents. In April this year, primary schools in Baarn closed their doors as a result of an email from a sender claiming to have stockpiled weapons ready to unleash “the most dreadful attack in the history of the Netherlands”.

Last week, five secondary schools and a trade school in Beverwijk and Heemskerk suspended all classes because of gang-related violence by pupils.