A handful of schools in Norfolk have received hoaxes containing threats against children.
Schools across the UK - including in Suffolk and Cambridgeshire - received the email, which reportedly contained threats against children leaving school on Wednesday afternoon.
Norfolk police confirmed they had received 16 reports of 'malicious hoax communications' being made to schools.
They said: 'Officers take hoaxes extremely seriously. They divert police resources and cause disruption and alarm to the public.
'Norfolk County Council is working to support police and the affected schools.
'Anyone with information should contact police on 101 or call Crimestoppers anonymously on 0800 555111.'
A Cambridgeshire Police spokesman added: 'We are aware of a series of malicious communications to schools across the country this morning.
'Enquiries are being carried out to establish the facts and forces are working together, along with the National Crime Agency, to investigate who is responsible.'
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