Nearly 50 schools in Bengaluru and about 40 in New Delhi received bomb threats through email on Friday morning, leading to students and staff being evacuated.

In Bengaluru, schools in several areas, including Rajarajeshwari Nagar and Kengeri, received identical emails claiming that several explosive devices containing trinitrotoluene, or TNT, had been planted in the classrooms, India Today reported.

The email added that the explosives had been “skilfully hidden in black plastic bags”.

Some of the schools that received the threat included MS Dhoni Global School, St Germain Academy, The Bangalore School, Bishop Cotton Boys’ School, Bishop Cotton Girls’ School, Baldwin Girls’ High School and Sophia High School, The Indian Express reported.

After the threats came to light, bomb detection teams, fire officials, local police and dog squads conducted searches at the schools. Some schools declared a holiday, while others asked students to wait until the premises were searched, The Hindu reported.

Bengaluru Police Commissioner Seemant Kumar Singh told the Deccan Herald that all the schools had been evacuated and security personnel were conducting searches there. “Nothing has been found as yet,” he added.

Similar emails were sent to about 40 schools in New Delhi, according to reports.

Unidentified Delhi Police officers told The Indian Express that 42 schools in the national capital received the emails at 10.53 pm on Thursday. The institutes informed the police and other authorities on Friday after discovering the email in their inboxes, the officers added.

Some of the schools that received the emails included Richmond Global School, Abhinav Public School, Sovereign School, Bharati Public School and St Xavier’s Senior Secondary School.

Search operations were being conducted by the police, along with the bomb detection and disposal squads and fire department officers at the schools, the newspaper reported.

The bomb threats in the national capital came two days after seven schools there received similar emails, which were later declared hoaxes. On Tuesday, Delhi University’s St Stephen’s College and a school had also received bomb threats through email.

Several schools, hospitals and colleges in the national capital have been receiving bomb threats over the past year.

In February, St Stephen’s College, along with two schools in Delhi and Noida, had received bomb threats. This had come a day after a 15-year-old Class 9 student was arrested for sending fake bomb threats to four schools in Noida. The student was presented before the juvenile court.

On December 13, six schools in Delhi received bomb threats through email. The senders had demanded about Rs 25 lakh in ransom. On December 9, more than 40 schools in the capital received similar threats, which the police later said were hoaxes.