The American Airlines aircraft, which had left New York on Sunday to India, had to land in Italy because the plane was threatened with a bomb.
The aircraft was above the Caspian Sea when the airline warned the crew of bomb threats, the airport sources tell AFP and Reuters.
The official source told ABC for Newsthat the unnamed person had sent the threat by email. The threat was unfounded.
There were 199 customers and staff on the airplane and was on its way to the New Delhi capital of India.
American Airlines has not responded to Reuters comment request on the subject.
Sources: AFP, Reuters