New Delhi: An all-out offensive will be launched against NDFB militants jointly by police, paramilitary forces and army in the wake of the group killing over 50 people in two districts of Assam.

The decision was taken at a high-level meeting chaired by Home Minister Rajnath Singh and attended by top officials of ministries of Home, Defence and paramilitary forces, sources said.

"This was an act of terror and we will deal with it accordingly, whatever action is required, we will take," Singh told reporters after the meeting.

Describing the attack on Adivasi villagers by the Songbijit faction of National Democratic Front of Bodoland (NDFB), as "very unfortunate and cowardly act", he said 50 companies (5000 personnel) of paramilitary forces have been rushed to Assam to assist the state government to deal with the situation arising out of the violence in Sonitpur and Kokrajhar districts.

The sources said army, which has its 4 Corps headquarters in Sonitpur district, has been asked to mobilise troops for the operations against the NDFB militants.

Singh, accompanied by Minister of State for Home Kiren Rijiju, will take stock of the situation there in the evening following a directive of Prime Minister Narendra Modi.