The school authorities informed the police after which search operation was carried out.
Police swarmed the British School in Chanakyapuri's diplomatic area here today and searched the premises for an hour after a threat call warned of an attack with an AK-47 rifle.
"The school authorities informed us about receiving a call at around 1 PM. The caller claimed he was armed with an AK-47 and threatened to kill all students," Deputy Commissioner of Police, New Delhi, Jatin Narwal said.
"Several police teams were rushed to the school and its entry and exit points closed. A thorough search was conducted in classrooms, washrooms and storerooms for an hour. It turned out to be a hoax call," he said.
Though no case has been registered in this regard so far, efforts are on to trace the caller and probe is underway, Mr Narwal said.
"We safely sent all the students back home after police informed us it was a hoax call and there was no threat. The campus is secure and everybody is home. All the security protocols are in place at the school," Director of the school Vanita Uppal told Press Trust of India.
In a message sent to all parents, the school authorities said, "The school was under lock-down for the last one hour. Police have given an 'all clear' and all students and staff are safe. Students were moved out in a safe and controlled manner, after school activities are cancelled. Buses will be delayed by 10-15 minutes."