Four schools in the Dutch city of Deventer were closed for a day after receiving emails threatening that non-Muslim students would be shot.

The threat came in the name of the Islamic State.

According to the Algemeen Dagblad news outlet, the school administration decided on the closures after consulting with law enforcement, the prosecutor’s office and the mayor of the city.

The badly worded text written in Dutch states that the attack had been planned for a long time, that no one would be spared, and that the motives will never be made public. In a separate email, they added that all non-Muslim students would be killed on the orders of the Islamic State.

Following a joint decision by the police and the city, the schools were closed for the day until security measures were put in place.

„We are taking both visible and less visible measures to protect students and staff,”

school management said.

Although the threat was being taken seriously, the management also noted that it was probably only „a bad joke”.