At least three schools in Amsterdam received bomb threats on Thursday, as did schools in Paris, London and Birmingham.

One source told the Telegraaf up to five schools in the Dutch capital could have been targeted. However, no explosives were found and the special measures operating in the city were withdrawn, the paper says.

According to the Parool, the Amsterdams Lyceum secondary school received a bomb threat at some point during the morning. ‘We reported the threat to the police and there was no reason for us to take it seriously,’ the school’s director Roel Schoonveld told the paper.

Police patrolled in front of the school for a time but the school was not evacuated.

On Tuesday, one campus of the British School of the Netherlands in The Hague was evacuated for a time because of a bomb threat. That warning appears to have been part of a string of threats at schools across Europe, including Britain, France and Norway.