An Indian Air Force plane carrying 29 people went missing on Friday on its way to Port Blair, capital of the Andaman and Nicobar islands, an air force spokesman said.
“A search operation is on. The plane was airborne at 8:30am (0300 GMT) and was supposed to land at Port Blair at 11:30,” Wing Commander Anupam Banerjee said.
The last contact with the plane, which was carrying service personnel and six crew members, was made around 15 minutes after take-off from the southern Indian city of Chennai, the spokesman said.
Surveillance aircraft and navy and coastguard ships have begun searching for the Russian-built AN-32 military transport aircraft, which is believed to have disappeared over the Bay of Bengal.
The Press Trust of India news agency reported AN-32s can fly for four hours without refuelling.
Last year, an Indian Coast Guard plane crashed south of Chennai, killing all three on board.