By Subir Bhaumik BBC News, Calcutta

The move, aimed at facilitating talks with separatist rebels of the United Liberation Front of Assam (Ulfa), is understood to be at Delhi's request.

"We have been asked to stop our offensive against the guerrillas and we have to comply with the orders," a military spokesman announced in Assam.

Earlier, troops killed two Ulfa leaders near Assam's north-east border.

Talks preparations

Officials in the Assam government confirmed that orders to stop the military operations had come from the prime minister's office.

Assam's leading human rights campaigner, Lachit Bordoloi, who is mediating between the two sides, welcomed the development.

"We were assured by the prime minister's office that the army would call off its offensive against the Ulfa to create an atmosphere conducive for talks.

"Now that they have kept their word, we will make expeditious arrangements for starting negotiations."

Mr Bordoloi is a member of a committee of civil society leaders set up by Ulfa to start negotiations with Delhi.

Earlier in the day, Ulfa's military chief Paresh Barua said that if military operations continued, his group would never start negotiations with Delhi.