A Russian-built Antonov An-32 was carrying service personnel and six crew members during a routine courier service to India's remote Andaman and Nicobar Islands in July 2016.

It last made contact with air traffic control 15 minutes after taking off from an air force base near the southern city of Chennai.

Search and rescue efforts at the time failed to find any trace of the aircraft after its disappearance.

The ministry of defence said a deep-sea drone surveying the ocean floor in the Bay of Bengal had found debris from a crashed aircraft at a depth of 3,400 metres (11,150 feet) around 140 nautical miles (310 kilometres) south of Chennai.

The images were "found to be conforming with an An-32 aircraft", the ministry said in a statement, adding that the discovery "at the probable crash site" pointed to the debris as "possibly belonging to the crashed IAF An-32".

No other aircraft have been reported missing in the area.

The An-32 is capable of flying for up to four hours without refuelling and is the Indian Air Force's workhorse transport aircraft.

But the IAF, which relies heavily on Russian-made equipment, has been blighted by a poor safety record.

An IAF source told AFP in 2016 that radar data from the missing aircraft showed it making a sharp left turn before rapidly losing altitude.

India's defence chief General Bipin Rawat was killed in 2021 alongside 12 other people when their Russian-made Mi-17 chopper crashed in the southern state of Tamil Nadu.

Two pilots were killed the following year when their Soviet-era MiG-21 fighter jet crashed during a training sortie in Rajasthan.

And last year a Russian-made Sukhoi Su-30 and a French-built Mirage 2000 collided in mid-air during exercises south of the capital New Delhi, killing one of the pilots.

In one of the worst disasters involving an An-32 in India, 20 people onboard died and three civilians were burnt to death on the ground when one of the planes crashed near a New Delhi airport in 1999.

The air force has gradually been getting rid of some of its older aircraft, some of which date back to the 1960s.

Experts have warned that India's delay in revamping its outdated military aircraft threatens national security.