Indian authorities mounted an extensive search-and-rescue operation for an Indian Air Force plane that went missing with 29 people over the Bay of Bengal on Friday.
The Antonov-32 transporter took off from the southern city of Chennai at 8:30 am (0300 GMT) and was to have landed at Port Blair in the Andaman and Nicobar Islands by 11:30 am.
A massive search operation was under way late Friday evening and was likely to continue overnight, Junior Defence Minister Subhash Bhamre told reporters.
Thirteen ships, five aircraft - including surveillance planes - and a submarine were deployed to search for the plane around the island group, located some 1,200 kilometres off the Indian mainland in the Bay of Bengal.
Air Force spokesman Wing Commander Anupam Banerjee said last contact with the plane was around 15 minutes after take-off.
Local media reported that three snags had been reported in the same aircraft during the month.
The plane was on a routine courier flight carrying service personnel and family members to the islands near the Mallacca Straits, where India has a key military base.
The plane, which had six crew and eight civilians or family members, may have plunged from an altitude of 23,000 feet, official sources told broadcaster NDTV.
It was not clear if the weather was bad, since heavy winds and rains are common during the monsoon season in the region between June and September.
The aircraft which was built in Soviet Russia and upgraded by Ukraine in recent years, can fly for up to four hours without refuelling, officials said.
The Indian Air Force operates 100 of the Antonovs. The Indian Air Force has reported a number of crashes over the past years, mostly involving Russian-made aircraft, that form the mainstay of the Indian fleet.
More than a dozen Antonov crashes have been reported in India since 1986. In the worst such accident, 22 people died when a plane crashed near the Delhi airport in 1999.