KOLKATA: A Delhi-bound Indigo Airlines plane carrying 138 passengers and 3 crew members returned to the airport on Sunday night after authorities received an anonymous phone call that a terrorist might be travelling on it.

The plane was already in the air for 30 minutes when it was asked to return after the phone call, which 'prima facie' appeared to be a hoax, Airport Authority of India officials said.

They said the call was being verified and the plane was taken to an isolated bay at N S C Bose International Airport for a security personnel search.

The passengers and crew had disembarked, they said adding the plane would take off after the search operation.