New Delhi, May 28 (PTI) - A Varanasi-bound IndiGo flight received a bomb threat at the airport here on Tuesday morning but a search of the aircraft found it to be a hoax, police said.

The bomb scare prompted authorities to evacuate all the staff and 176 passengers onboard and launch a search operation, they said.

The passengers will be flown to Varanasi in another plane, which is expected to take off at 11 am, an IndiGo spokesperson said in a statement.

"At around 5 am, an information was received regarding a paper found in the lavatory of an Indigo flight scheduled to depart for Varanasi, with the phrase 'bomb @5.30' written on it," a senior police officer said.

A thorough inspection was conducted, the officer said, adding, "No suspicious items were found. It was a hoax threat. Further investigation is underway."

The officials said the threat was found written on a piece of paper in a lavatory by the pilot when the Indigo 6E2211 flight was preparing to leave from the Indira Gandhi International Airport.

A security operation was launched after the pilot informed the control room, they added.

"All necessary protocols were followed and the aircraft was taken to a remote bay as per guidelines by airport security agencies," the IndiGo spokesperson said.

All passengers were safely evacuated via the emergency exits," the spokesperson added.