An investigation has been launched after malicious emails were sent to a number of schools in the North West, police have said.
Both Chester Constabulary and Greater Manchester Police (GMP) said they were looking into the messages.
Lache Primary School, in Chester, initially notified parents on its Facebook page that they would be unable to pick up their children after the message had been received.
In a statement, it said: “We are aware that parents have arrived outside school.
“To repeat, we cannot let any children out or any parents in. As we have stated this is a precautionary measure following an unpleasant email that has been sent to a number of schools in Cheshire, Liverpool and Manchester.
“There is not a threat on site. We have locked down the school to ensure that everyone is safe. Which they are.
“The police are dealing with the situation and are very happy with the measures that we have in place.”
It later changed that advice, saying the email was “believed to be a malicious hoax” and children would be allowed to leave by year group.
Has your school been affected? Email us at news@skynews.com.
Blacon High School, also in Chester, said it had put additional measures in place after receiving the email, but added: “For reassurance, Blacon High School is not currently in lockdown.”
In a statement, Chester Constabulary said it was “aware of an email which had been sent to a number of schools in Chester and Ellesmere Port which made threats to pupils and staff”.
It added: “An investigation has been launched and officers have been attending schools to provide reassurance.”
Detective Chief Inspector Justin Hancock said: “We would like to reassure parents that this is believed to be malicious and we are doing everything we can to locate the person responsible for these emails.”
GMP said it was looking into “reports of malicious communications being sent to schools across the city of Manchester”.
It added: “The reports are currently being investigated to ensure the safety of schools and local communities.”
Chief Inspector Chris Boyd said: “We take reports of this nature very seriously and whilst we have not advised any schools to close, our officers will nevertheless be stepping up their high-visibility presence around schools at the end of the day today to provide reassurance to them and the wider public.”