Specific intelligence inputs have indicated that the Kabul - Delhi Air India flight could be targeted by Islamic State militants or the Taliban.
The Delhi airport is on high alert after intelligence agencies warned that a possible hijack attempt might be made on an Air India flight bound for Afghanistan. The threat perception is based on messages that surfaced earlier, indicating that both Islamic State militants and the Taliban may choose to target India, sources told NDTV.
Security agencies have indicated that an Air India flight to Kabul could be targeted as it is the national carrier and senior officials travel on it to Afghanistan.
The fresh alert - issued to the Bureau of Civil Aviation Security - comes in the wake of a general alert issued in view of US President Barack Obama's visit to India later this month. The US President is the chief guest at the Republic Day parade to be held in Delhi on January 26.
Security had already been tightened at the airports across the country.
India is currently training the Afghan National Army and is participating in the reconstruction efforts in the country.
Indians in Afghanistan have been frequent targets of militant attack - the last big attack took place at the Indian Consulate in Herat in May 2014 by four heavily-armed militants. The gun-battle to sanitise the place lasted several hours. None of the consulate staff were injured.
The Al Qaeda has been trying to set up a base in the Indian subcontinent. In September, a video by the group's chief Ayman al-Zwahri surfaced, according to which Asim Umar, chief of Al Qaeda's Sharia Committee for Pakistan, has been named the leader of the new group - called the Qaedat al-Jihad.
On Saturday, an anonymous telephone call threatening that an Air India plane would be hijacked was made to the Kolkata office of the state-owned carrier, police said. The alleged caller has been arrested.
A senior officer of Kolkata Police said it was a brief call in Bengali threatening that an Air India flight would be hijacked. The official, however, did not specify which flight would be targeted.
Senior officials of Bureau of Civil Aviation Security, CISF and AAI held a meeting in Kolkata on Saturday night to review the security measures.