New Delhi: Security was Sunday tightened at the Indira Gandhi International (IGI) airport here following an intelligence alert that terrorists may target Air India flights going to Afghanistan, an official said.

The Central Industrial Security Force (CISF) which looks after the airport's internal security has been asked to be on alert and keep a tab on the activities of every person.

Besides, Delhi Police, which is in charge of security outside the airport, was also put on alert.

"Security has been extended and policemen have been increased," Deputy Commissioner of Police (IGI) M.I. Haider told IANS.

CISF spokesperson Hemendra Singh said security has been tightened since the last two months.

"Flights going to Afghanistan are being monitored carefully," he said.

Air India officials were not available for comment even after repeated attempts.