London/Mumbai: A US-bound flight of Air India from Mumbai, was forced to make a precautionary landing at London's Stansted Airport on Thursday (June 27) following a bomb scare. However, the threat has turned out to be a hoax.

As the threat was issued, fighter jets were employed to escort the aircraft.

According to security agency sources, the flight was diverted to London after Mumbai airport authorities received an e-mail from two unidentified persons named - Sergie Seliznev and Nataliya Zhmurina - threatening that Air India flight would 'explode in air' along with two other airlines.

Besides Air India, the alleged threat was also for the Lufthansa's Mumbai-Munich and Swiss Air's Mumbai-Zurich flights, which had already landed by the time the call was declared as "specific at 10.30 am," sources added. 

Queries sent to Lufthansa did not elicit any response.

The registered baggage and cargo, which were supposed to be loaded on the Air India flight, but could not be uploaded, at the Mumbai airport were being extensively checked following the threat.

Mumbai airport has been on alert following Thursday's development, they said.

"AI 191 Mumbai-Newark of June 27 has made a precautionary landing at London's Stansted airport due to a bomb threat," the national carrier said.

According to sources, the two men in the e-mail claimed that they are the "members" of the Caucasus Emirate, who were fighting for the establishment of a global Shariah.

"We do not recognise the State of Israel, consider it an occupier of Palestine and lay down our heads for its destruction. For this, we have prepared and delivered a polysiloxane solution to be added to the jet fuel with the help of service technicians," the letter read.

In the e-mail they claimed "For Air India flight, a nitrogen-free powerful explosive device has been placed in the flights baggage, which will explode in the air".

"These flights will suffer a plane crash," they threatened in the e-mail, according to sources.

Earlier, the airline, in a tweet, said that the plane made a precautionary landing at London's Stansted airport due to a "bomb threat."

"Our runway is fully operational following a precautionary landing of Air India flight. We are sorry for any disruption caused by the incident and would like to thank you for your patience," Stansted Airport said.