He was 74.

On Friday, the rebel leader died in a hospital at 7.45pm Myanmar time, said his group's spokesman T. Pheiray. But the location where he had died was not clarified though sources say he passed away in a Yangon government hospital after suffering a stroke.

S S Khaplang was the leader of the National Socialist Council of Nagaland-Kaplang or NSCN-K.

Shangwang Shanyung Khaplang who belongs to the Hemi Naga tribe in Myanmar's Sagaing region, started off with the now defunct Eastern Naga Revolutionary Council formed by Burmese Nagas to support the insurrection in India's Naga hills in the late 1950s.

He sided with the China-trained Naga rebel leaders Thuingaleng Muivah and Issac Chisi Swu when they opposed the 1975 Shillong Accord signed by the leaders of the Naga National Council.

But he later fell out with Muivah and Swu and his supporters massacred nearly 190 Indian Naga fighters in the Sagaing bases in 1988.

The National Socialist Council of Nagalim they formed has now split up into four factions, with Khaplang and Muivah factions involved in a bitter fratricidal feud for years even as they entered into a ceasefire agreement with the Indian government after 1997.

But two years ago, Khaplang reneged on the ceasefire, upset as he was with Delhi's refusal to involve his faction in negotiations that it was having with the Muivah faction.

Khaplang then formed a rebel coalition UNLFSWEA with three other anti-Indian rebel groups.

His fighters attacked and killed large number of Indian troops, provoking an Indian cross-border raid in July 2015 by Para commandos.

Khaplang however maintained the ceasefire with the Myanmar government which he had signed up to in 2012.

Pheiray said Khonga Konyak has replaced him as the leader of the rebel faction whose militancy had strained India-Myanmar relations.

India's ruling BJP leader Ram Madhab confirmed Khaplang's demise in a tweet.

According to Aung Naing Oo, in 2015, he was gravely ill and requested help from the Myanmar government. The then Chief Negotiator and Union Minister U Aung Min agreed to the Naga’s request. He also informed the Embassy of India about Myanmar government’s intention to provide medical care to the ailing leader who was wanted in India. It was critical for the government to help an ethnic leader but at the same time had to pay attention to bilateral relationship with India.

India may find it easy to bring his faction to the table now that the Burmese Naga leader is dead.

The former Indian Home Minister L K Advani had ruled out talks with Khaplang on grounds he was a foreign national.