The Kempegowda International Airport was subjected to heightened security protocols after a hoax bomb threat was received by the airport security force, police sources said on Thursday.

According to sources, the email, sent on Wednesday night in the name of a terrorist, warned of two bombs being planted--one as part of "Plan A" and a backup under "Plan B" in case the first one failed.

It also claimed that an explosive device had been placed inside a pipeline in the airport toilet.

Security agencies conducted a comprehensive inspection of the premises. After detailed checks, officials confirmed that no explosives were found and termed the threat a hoax.

A case has been registered against the email IDs used to send the threat, and a formal investigation is underway.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.