General Bipin Rawat, India's first Chief of Defence Staff, his wife Madhulika and 11 other armed forces personnel died on Wednesday after the military helicopter they were travelling in crashed near Coonoor in Tamil Nadu, the Indian Air Force said.
The lone survivor, Group Captain Varun Singh, is currently under treatment at a military hospital in Wellington, it said.
The Chief of Defence Staff had left the Palam airbase in an IAF Embraer aircraft at 8.47 am and landed at Sulur airbase at 11.34 am.
He took off from Sulur in a Mi-17V5 chopper at around 1148 am for Wellington, official sources said.
The chopper crashed around 12.22 pm, they said.
Rawat had survived a helicopter crash six years ago, in 2015, when he was a Lt General.
The Chief of Defence Staff was scheduled to deliver a lecture at Defence Services Staff College in Wellington.
Those killed in the crash included Brigadier L S Lidder, the military adviser to the Chief of Defence Staff, and staff officer Lieutenant Colonel Harjinder Singh.
The other personnel killed are Wing Commander P S Chauhan, Squadron Leader K Singh, Junior Warrant Officer Das, JWO Pradeep A, Havildar Satpal, Naik Gursewak Singh, Naik Jitender Kumar, Lance Naik Vivek Kumar and Lance Naik Sai Teja.
The prime minister-led Cabinet Committee of Security met in the evening and paid glowing tributes to Gen Rawat, it is learnt.
It is not immediately known whether the government will appoint a new Chief of Defence Staff soon.
The mortal remains of Gen Rawat and his wife are likely to arrive in the national capital on Thursday evening and their cremation will take place on Friday in Delhi Cantonment, officials said.
Defence Minister Rajnath Singh said he was 'deeply anguished' by the sudden demise Gen Bipin Rawat, his wife and 11 others in an 'extremely unfortunate helicopter' accident in Tamil Nadu.
'Gen Bipin Rawat, Chief of Defence Staff (CDS) was on a visit to Defence Services Staff College, Wellington (Nilgiri Hills) to address the faculty and student officers of the Staff Course today,' the IAF said in a statement.
'With deep regret, it has now been ascertained that Gen Bipin Rawat, Mrs Madhulika Rawat and 11 other persons on board have died in the unfortunate accident,' it said.
The IAF had confirmed about the accident around 2 pm, saying the Mi-17V5 helicopter with Gen Rawat on board met with an accident near Coonoor.
It has already ordered an Inquiry to ascertain the cause of the accident.
As the Chief of Defence Staff, Gen Rawat was overseeing the implementation of an ambitious tri-services modernisation plan to bring synergy among the armed forces and enhance their overall combat capabilities.
'My heart goes out to the families of those who lost their loved ones in this accident. Praying for the speedy recovery of Gp Capt Varun Singh, who is currently under treatment at the Military Hospital, Wellington,' Singh tweeted.
'General Rawat had served the country with exceptional courage and diligence. As the first Chief of Defence Staff he had prepared plans for jointness of our Armed Forces,' he said.
Gen Rawat had served as the Chief of the Indian Army from December 17, 2016, to December 31, 2019.
He was appointed as India's first Chief of Defence Staff on December 31, 2019.
Army Chief Gen MM Naravane and all ranks of the force paid heartfelt condolences on the untimely demise of Ge Rawat his wife and 11 others.
'The dynamic and inspiring leadership of General Bipin Rawat shall remain eternally etched in our memories. The #IndianArmedForces will forever remain indebted to his invaluable contributions,' the Army tweeted.
Gen Rawat's wife Madhulika was serving as the president of the Defence Wives Welfare Association (DWWA).