Pupils were sent home this morning after a threatening phone call was made to a school.
Police searched Orchard Mead Academy in Hamilton, Leicester, after staff informed the authorities and it has now closed for the day.
Children were moved to a safe area after the call was received earlier today.
LeicestershireLive report that lessons will resume on Wednesday after the all-clear was given.
The Mead Educational Trust, which runs the secondary school, have said the call is now believed to have been a hoax but state their decision was taken to close for the day as the incident was upsetting for many students and parents.
Parents were first informed something was wrong at 9.37am this morning when they received a message from executive principal Mark Oldman.
Messages to parents revealed the police were involved and giving the school guidance on how to proceed.
Mr Oldman told them their children were safe and invacuation procedures were being followed. This meant the pupils remaining inside, but being moved to a safe area.
A second message to parents reiterated that the pupils were safe and there had been no “danger or threat in school”.
It read: “While I appreciate your concerns, we will keep your children safe.
"We are being given instructions from the police in line with our invac policy. Your children are safe. We anticipate the school day returning to normal soon."
However, one said the school held a meeting at around 11am and the decision was made to send the pupils home within the hour.
They added: “The children have messaged us parents petrified as they had not been told what was going on. They had to hide under the tables and close the blinds.”
A spokesperson for the Mead Educational Trust said: “We can confirm that Orchard Mead received a malicious telephone call this morning that triggered our lockdown procedures. The school immediately called the police, who have thoroughly searched the site and given the all clear.
"They believe the call to have been a hoax. The school has been in contact with parents throughout the morning updating them as information was available.
"Understandably this incident was upsetting for many students and parents so we have made the decision to close the school for the rest of the day.
"Lessons will resume as normal tomorrow. We have reassured parents that every decision we make is to ensure the safety of our children and staff.”
A spokesman for Leicestershire Police said: "Shortly before 8.40am today, staff at Orchard Mead Academy reported that a malicious phone call had been made to the school.
"A further call was later received stating that a pupil had identified themselves as the person who had made the call. Officers have attended the school and no risk of harm has been identified."
