The state government had ordered security forces to cut back operations against the National Democratic Front of Bodoland (NDFB) after the group said last week it was ready to halt its two-decade insurgency, a minister said.

"After we got a written communique from the NDFB expressing their desire for a ceasefire, we on our part have decided to reciprocate the offer," said Health Minister Bhumidhar Barman, part of a government team in talks with the rebels.

"We have communicated the details of the ceasefire offer to New Delhi and are expecting a positive response by Saturday, mentioning the modalities and other ground rules for the truce," Barman told AFP.

"We believe the NDFB's offer is genuine and hence it is natural that the security operations be limited until the ceasefire proposal gets a formal nod from the central government," he said.

Assam chief minister Tarun Gogoi last month asked the NDFB and another rebel group, the United Liberation Front of Assam (Ulfa), to agree to a ceasefire by October 15 and then hold peace talks.

The NDFB accepted the offer, but the Ulfa rejected it.

The outlawed NDFB, which is fighting for an independent homeland for the Bodo tribe in Assam, carried out a spate of killings in Assam over the last fortnight before announcing its acceptance of the ceasefire offer.

Observers have said the attacks were aimed at strengthening the group's bargaining hand before it sits down for negotiations with the government.

The NDFB is one of the region's frontline rebel armies with an estimated 1,500 fighters, who largely carry out hit-and-run attacks.

The Bodos, a primitive tribe most of whom are now either Hindus or Christians, account for about 10 percent of Assam's 26 million people and settled mostly in western and northern part of the state.