“Rawat was an outstanding soldier. A true patriot, he greatly contributed to modernising our armed forces and security apparatus,” Modi said. “His insights and perspectives on strategic matters were exceptional.”

Defence Minister Rajnath Singh said Rawat “served the country with exceptional courage and diligence”.

The air force said an inquiry had been ordered into the accident.

Television images from the crash site showed plumes of smoke billowing from the debris as local residents tried to put out the fire and remove bodies from the wreckage.

Rawat was headed to the Defence Services Staff College (DSSC) to address students and faculty from the nearby Sulur air force base in Coimbatore.

The chopper was already making its descent at the time of the crash. It came down around 10 kilometres (six miles) from the nearest main road, forcing emergency workers to trek to the accident site, a fire official said.

The sole survivor of the crash, a captain working at the DSSC, was being treated for his injuries at a nearby military hospital, the air force said.

Indian Foreign Minister Subrahmanyam Jaishankar said he was “deeply shocked” by the accident and Rawat’s death.

“We worked closely together in the last few years. It is a huge loss to the nation,” he said.

Rawat came from a military family with several generations having served in the Indian armed forces.

The general joined the army as a second lieutenant in 1978 and had four decades of service behind him, having commanded forces in Indian-administered Kashmir and along the Line of Actual Control bordering China.

Rawat was chief of the 1.3 million-strong army from 2017 to 2019 before his elevation to defence services chief, which analysts said was to improve integration between the army, navy and air force.

In 2015, Rawat oversaw Indian “surgical strikes” into neighbouring Myanmar, when para-commandos entered the country to attack Naga rebels who had ambushed and killed Indian troops.

In 2017, he awarded a gallantry medal to an army officer who had tied a civilian to the front of his jeep in Kashmir, where rebels are fighting Indian rule.

The incident sparked controversy within India and outside, with rights groups saying the officer used the man as a human shield against stone-throwing protesters. Rawat said the officer’s actions were within the rules because the army was facing a “dirty war” in the disputed region and had to fight using “innovative” ways.

Rawat earlier survived a helicopter crash in 2015 in the northeast state of Nagaland.

The type of military transport helicopter that crashed on Wednesday, Mi-17V5, first entered service in the 1970s and is in wide use by defence services around the world. It has been involved in a number of accidents over the years.

Fourteen people died in a crash last month when an Azerbaijani military Mi-17 chopper went down during a training flight.

In 2019, four Indonesian soldiers were killed and five others wounded in central Java in another training accident involving the aircraft.

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Additional reporting by AP