The United Liberation Front of Asom (ULFA) on Thursday reiterated its demand asking migrant workers, mostly from Bihar, to quit Assam.
"Many times we appealed to the Hindi-speaking people that the conflict running in Assam is with colonial India, so go away from here as soon as possible. Again we appeal to those people coming from colonial India to stay away during this conflicting period," the ULFA said in its fortnightly newsletter Freedom.
Authorities have blamed the ULFA for a wave of attacks over January 5 to January 8 in which 73 people were killed, 61 of them being migrant workers.
The ULFA have not owned responsibility for the violence and instead blamed New Delhi for the massacres.
"For the last few days people are ceaselessly condemning the ULFA by holding it responsible for the attacks on Hindi-speaking people. We once again reiterate that ULFA will never entertain the dirty policy of acquiring its goal by gambling with the lives of innocent people," the rebel statement said.
"Over the years the Indian colonial rulers are venturing into the tactics of bombing in public places, buses, trains and then people blame the ULFA. To tarnish ULFA's image, the colonial government's functionaries are utilising this opportunity."
The ULFA, fighting for an independent homeland since 1979, said it would step up its armed campaign.
"They (New Delhi) talk of dialogue on the one hand and announce full-fledged military operation on the other. ULFA is destined to give proper reply to this dual policy by boosting the struggle," the statement said.
"There is no way left other than intensified resistance struggle if India does not tackle the Assam-Indo political conflict politically and opt for displaying military might. Masses will rightly choose their path for resolution."
The ULFA threat to step up its campaign comes in the wake of a major counter-insurgency operation launched in Assam and Arunachal Pradesh.
Prime Minister Manmohan Singh had on Tuesday said 'terrorism will not be tolerated' and dealt with 'firmly'.