Three locations of the Etty Hillesum Lyceum in Deventer remained closed on Tuesday morning after the school received an email from a person threatening to carry out a shooting.

A spokesman for the school confirmed to local broadcaster Oost that the message was sent on Monday and police had been informed.

The e-mail, which is also doing the rounds on social media, said “I will kill everybody without mercy and spare no one”. It mentioned two locations in particular as targets.

Earlier on Tuesday the school said the threat may “not be real” but that all three locations would remain closed as a precaution. A decision to reopen the schools will be made following a meeting with police and the local authorities.