Mumbai: Major airports across the country have been put on alert following the warning of an attack.

As per reports, an anonymous threat letter was received which warned that two flights one each originating from Mumbai and Ahmedabad airports could be targeted.

Authorities believe the letter is a hoax, but are not taking any chances and security has been stepped up.

A bomb disposal squad and an anti-hacking unit were this morning deployed at the Kochi airport.

Similar emergency mechanisms have also been activated at other airports.

Reports said the threat letter was received by the director of the Airports Authority of India. It warned that the Friday night flight from Ahmedabad to Mumbai and early Saturday morning flight from Mumbai to Kochi will be targeted.

As per reports based on intelligence inputs, suicide bombers could board two Air India flights from Mumbai and Ahmedabad airports on Saturday morning.

The Bureau of Civil Aviation Security (BCAS) has also issued a letter to airports in connection with the threat.

It reads: "An input received says: Air India flight on the midnight of October 24 (early morning of October 25) from Ahmedabad to Mumbai and early morning flight from Mumbai to Kochi on 25th morning at 0500 hrs. Suicide bomber in each flight separately. Please check thoroughly. Secondary security checks may be carried out at Ahmedabad and Mumbai airports for all flights around the concerned dates."