Security personnel at the Indira Gandhi International Airport (IGI) went on a high alert after an e-mail threat by the Deccan Mujahideen, the militant outfit that had claimed responsibility for the Mumbai terror attacks.
The email -- that was intercepted by the Gujarat Police -- threatened to blow up the Bombay Stock Exchange and the IGI airport.
There was an unprecedented security cover at both the terminals of the airport and security personnel were seen guarding the parking lots and patrolling the airport premises.
A senior Central Industrial Security Force (CISF) officer confirmed that they had increased security at the airport on specific directions.
Though the IGI airport already has a security mechanism in place, the vigil was mounted, especially on the city side.
"We in collaboration with the Delhi Police increased the security outside the airport as there is threat that terrorists could carry out an attack outside the airport," said a CISF official. Intelligence Bureau officials examining the email said that there was a specific mention of the BSE and Delhi airport in it.
More dog squads had been pressed into action to check the baggage. Security at both the international and domestic terminals was stepped up several notches with anti-hijack and anti-sabotage measures put in place, police said. With security personnel taking no chances, frisking and manual checking of baggage had been intensified.