India's top military commander has died in a helicopter crash in the southern Indian state of Tamil Nadu, the air force says.

Chief of Defence Staff Gen Bipin Rawat, his wife and 11 others were travelling in the Mi-17V5 helicopter that came down in hills near Coonoor city.

One passenger has been taken to hospital.

Gen Rawat, 63, was appointed India's first-ever Chief of Defence Staff in January 2019.

Images from the crash site showed thick plumes of smoke billowing from the mangled remains of the helicopter, and local people trying to put out the fire.

The helicopter had just taken off from the army base in Sulur, and was headed for Wellington town, less than 100km (62 miles) away.

The Indian Air Force said it had ordered an investigation into the accident.

Although the Mi-17V5 is among the most sophisticated military transport helicopters, India's ageing air force fleet is often blamed for a high number of crashes.

In 2017, seven military personnel were killed in a crash in the north-eastern state of Arunachal Pradesh. The helicopter was on a training sortie.

A year before that, another of the helicopters had crashed immediately after take-off during a military drill in the northern state of Uttarakhand. No casualties were reported then.