LEIDEN, Netherlands (AFP) - Dutch police have arrested a former British School pupil in connection with a shooting threat that led to the closure of schools in university city Leiden, the school said on Monday.

"We have been informed that a former student of the British School in the Netherlands (BSN) has been arrested in connection to threats made against a Dutch school in Leiden," a statement said.

Police in Leiden, just northeast of The Hague, confirmed one person had been arrested.

"Someone was arrested in connection with the threat and we're continuing our investigations," a police spokeswoman said, declining to give her name.

The British School said that the pupil was expelled in October 2011 "after incidents regarding his behaviour and has therefore not attended the school for over a year."

Police informed the school that there was never a threat to the British School or to its students, the school said, adding that it had remained open on Monday.

Earlier, armed police were deployed and schools closed in the city after an apparent student threat to "shoot my Dutch teacher and as many students as I can".

A decision was taken late Sunday night to close secondary schools to thousands of pupils following a tip-off by Swiss police concerning a threat made on the Internet over the weekend.

"I will shoot my Dutch teacher and as many students as I can," said the anonymous message in English on the US-based online forum 4chan.org. "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 ended.

In a statement late Sunday, law officials said they did not know against which school the threat had been made and warned parents not to send their children to class.