The Delhi Police on Wednesday said that a bomb threat sent to multiple schools in the national capital earlier in the day appeared to be a hoax, adding that it had “conducted thorough check of all such schools as per protocol”.

“Nothing objectionable has been found,” the Delhi Police said in a statement on social media.

Nearly 100 schools in Delhi and the National Capital Region had received a bomb threat on their official email IDs around 4.15 am, NDTV reported. Subsequently, officials from the police and the fire department conducted inspections in the schools.

Senior police officer Rohit Meena said that upon receiving word of the threat email sent to several schools, the schools were closed and the students were sent back home. “Checking is underway at all the schools and our technical wing is investigating the email,” he said. “Through the initial investigation, it seems that this is a mass email.”

Later in the day, Lieutenant Governor of Delhi Vinai Kumar Saxena told reporters that the police had traced the origin of the emails and that an investigation was underway. “I am assuring citizens of Delhi that the police are alert, getting leads, and will take strict action,” he said.

On a preliminary reading, the emails seem to have been sent from Russia, The Indian Express reported quoting unidentified officials.

Central agencies were also looking into the incident.