'Their motive is to falsely implicate the NSCN as a terrorist organization in the eye of the world,' the statement said.

The NSCN-IM, led by guerrilla leaders Isak Chishi Swu and Thuingaleng Muivah, had entered into a ceasefire with New Delhi August 1997.

The two sides have since held at least 55 rounds of peace talks aimed at ending one of South Asia's longest running insurgencies that claimed an estimated 25,000 lives since India attained independence in 1947.

The NSCN-IM is one of the oldest and most powerful of about 30 rebel groups in India's northeast and sought to create a Greater Nagaland by slicing off parts of neighbouring states that have Naga tribal populations.

The three regional governments of Assam, Manipur, and Arunachal Pradesh have already rejected the NSCN-IM's demand for unification of Naga-dominated areas. New Delhi, too, has rejected demands for unification of all Naga-inhabited areas.