New Delhi, Aug 3 (PTI) With an aim of ending insurgency in Nagaland, government today signed an accord with key outfit NSCN(IM) which Prime Minister Narendra Modi described as a "historic" step to usher in peace in the state.

The pact was signed in the presence of the Prime Minister, Home Minister Rajnath Singh and National Security Adviser Ajit Doval by the outfit's leader T Muivah and government's interlocutor R N Ravi at the PM's residence here.

The signing of the pact is the culmination of over 80 rounds of negotiations that spanned 16 years with first breakthrough in 1997 when ceasefire agreement was sealed.

While the National Socialist Council of Nagaland (Isaac-Muivah) is the biggest Naga rebel group which has been maintaining the ceasefire, another faction led by S S Khaplang continues to indulge in violence and was believed to be behind the deadly attack on army in Manipur in June that left 18 soldiers dead and 18 injured.

It was not immediately clear whether the agreement meets the main demand of NSCN(IM) for integration of all Naga-inhabited areas in the North East across Manipur, Arunachal Pradesh and Assam.

Details and execution plan within this framework agreement will be released shortly, official sources said after the accord in which Doval played the central role.

Describing the accord as "historic", Modi said, "Today, we mark not merely the end of a problem, but the beginning of a new future."

He added, "We will not only try to heal wounds and resolve problems, but also be your partner as you restore your pride and prestige."

Muivah said the government and Nagas were entering a "new relationship" but added that "beginning from now, challenges will be great." .