Bomb threats have been received at hundreds of schools across the country today.
Humberside Police said 19 'hoax' threats have been received in East Yorkshire and North Lincolnshire, with more than 400 received nationally.
A spokesman said: "We would like to reassure parents after a number of schools across East Yorkshire and Northern Lincolnshire received fake bomb threats this morning.
"Nationally, more than 400 schools and colleges have received emails claiming a device has been planted and demanding cash.
"Locally, 19 schools have been in touch to say they have been sent the email."
Detective Superintendent Tony Cockerill, of Humberside Police, said: "We have been liaising with our counter terrorism colleagues across the country and it is not believed that the threats are credible.
"We have spoken to all schools who have contacted us, reassured them that there is no need to evacuate and offered them security advice."
It has not yet been revealed whether any have been received in South Yorkshire, but Derbyshire Police said a number of schools and colleges in its area have been affected.
A spokesman said: "We have received reports of threatening emails received by many of our region’s schools.
"Many similar instances have been reported across the country and we do not believe any of the threats being made in the emails to be credible or viable."
North Yorkshire Police has confirmed that a number have been received there.
A spokesman said: "We have had a number of reports this morning about a bomb hoax at many of our schools across the county.
"This is believed to be a national issue.
"Our Cybercrime Unit Detectives, supported by local officers, have looked at these incidents and it is not believed there is any genuine threat. We are working with schools to offer reassurance and address any concerns."
More to follow.