The Indian air force Friday lost contact with a transport plane carrying 29 people to islands in the Bay of Bengal, the defense ministry said.
The AN-32 aircraft took off from the southern city of Chennai at 8.30 a.m. and was flying over the bay to the city of Port Blair in the Andaman and Nicobar islands, said Nitin Wakankar a spokesman for India's defense ministry.
The flight, covering 1,375 kilometers (854 miles), was supposed to last three hours but there was no contact for nearly three hours beyond its arrival time.
Indian air force spokeman Anupam Banerjee told reporters that the last communication from the aircraft was about 15 minutes after take-off.
Wakankar said the Russian-made aircraft could go for four hours without refueling.
A massive search by the air force, navy and coast guard has been launched for the missing plane.
No other details were immediately available.