Isak Chishi Swu and Thuingaleng Muivah during a press conference
Leaders of the National Socialist Council of Nagaland (NSCN I-M) Isak Isak Chishi Swu (R) and Thuingaleng Muivah raises his hand during a press conference in New Delhi January 23, 2003. Talks to end India's longest running insurgency wound up without a breakthrough on Thursday but the rebels from the northeast and the government said they were satisfied with the progress and would meet again.REUTERS/Fayaz Kabli

Isak Chishi Swu, the chairman of the Nationalist Socialist Council of Nagalim (Isak-Muivah), or NSCN-IM, died at Fortis Hospital, Delhi, on Tuesday. He was 87.

Isak, who was also the co-founder of NSCN-IM along with Thuingaleng Muivah, had been undergoing treatment at Fortis Hospital in the national capital since July 2015.

He couldn't witness the historic signing of the peace accord between the Indian government and the NSCN-IM on Aug. 3, 2015, due to his ill health.

It was speculated that the peace accord, an attempt to end over six decades of Nagas' struggle for self determination, was signed in haste because of Isak's deteriorating health.

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