In 1990, India launched Operations Rhino and Bajrang against Assam separatist groups, which caused the militants to relocate their camps to Bhutan.

[3] In the 1990s, ULFA and NDFB, two groups targeted by the Indian operations, allegedly assisted the government of Bhutan in expelling the ethnic Lhotshampa population and occupied the abandoned land.

[6] In 1996, Bhutan discovered a large number of camps on its southern border with India, which were set up by various separatist movements including ULFA, NDFB, BLTF, and KLO.

Other reports suggested that the attackers could be part of a special force raised by the Bhutanese army under Indian guidance, or even local vigilante groups.

[5] The spate of attacks on ULFA hideouts in southern Bhutan and Bhutanese government reactions to it demonstrated the state of the deterioration of Bhutanese-ULFA relations.