Officials involved in aviation security said the call was received at 11:42 pm last night at the control room of the airport operator of the Indira Gandhi International Airport (IGIA). "China eastern ki flight mein bomb hain (there is a bomb on a flight of China Eastern airlines)," a man claimed.
The man who made the call from his mobile phone indicated that the threat was on a China or a Hong Kong-bound flight, they added.
They said a bomb threat assessment committee (BTAC) was immediately convened at the airport, involving CISF security officers and IGI officials, and a full alert was declared at the airport entailing enhanced frisking of arriving passengers and their luggage.
A second round of body search was also carried out before the passengers boarded two flights bound for Shanghai and Hong Kong in the early hours today, they said.
The man who made the call was again contacted by the BTAC but he did not give a clear reply and cut the phone saying "he cannot help beyond this and that he was in a party".
The call was declared a hoax at 1:17 am, over an hour after the security personnel went into a tizzy, they said.
The police has registered a case and is investigating, they added.