A MASS email hoax threatening a bomb attack was sent to 400 schools across the UK - forcing some to be evacuated.

Schools in the North East, London, Bristol and Humberside received the emails - thought to have been sent from the United States - claiming an explosive had been placed on the grounds.

3 More than 400 schools received emails across the North East, London, Bristol and Humberside Credit: PA:Press Association

The messages went on to say the bombs would go off unless a cash payment was sent.

Cops at Northumbria Police were among those investigating the threats and the force confirmed in a statement on Monday morning there was no “viable threat” to the schools.

A spokesperson for the force said: “We have received reports from a large number of schools in our region that they have received threatening emails.

“The emails inform the school that a bomb has been placed on the grounds and will be detonated if they don’t hand over cash.

3 Bristol Free School, which was on lockdown because of a bomb threat but has recently reopened Credit: SWNS:South West News Service

3 A message to parents of pupils at Manor Park Primary Academy in Sutton, Surrey regarding the hoax Credit: Guzelian

We have had a number of calls this morning about a bomb hoax at many of our region's schools. All of the schools have been spoken to and there is not believed to be any viable threats #ProudToProtect pic.twitter.com/iGafyMfAvx — Northumbria Police (@northumbriapol) March 19, 2018

“Detectives have looked into the emails - which appear to originate from the US - and can confirm that there is no viable threat.

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“Schools have been visited by police to reassure them that the incident is being treated as a hoax and address any concerns.

“We take all incidents of this nature extremely seriously and an investigation into the emails in question are under way.”

Anyone with information on the hoax is urged to contact 101, quoting log 218 19/03/18.

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