Dutch police have arrested a former British School pupil in connection with a shooting threat that led to the closure of schools in the university city Leiden.

22 schools in the city had been told to stay closed as a precaution after a shooting threat was made.

Someone posted a message on US-based website 4chan.org saying they planned to shoot a teacher and as many students as they can.

The post read;

"I will shoot my Dutch teacher and as many students as I can," said the message in English, posted anonymously.

It's at a school in the Dutch city of Leiden..." it said, chillingly adding "for more proof, I will be using a 9mm Colt Defender.

Oh, and I'm using a proxy, the police is not gonna find me before tomorrow," the message ends.

The city's Mayor made the decision to close schools as a measure of pre-caution, saying he didn't want to take any chances.