Armed militants of the outlawed Dima Halam Daogah (DHD) attacked three villages overnight on Saturday and set ablaze homes of Karbi tribesmen in the district, about 320 km east of Guwahati, a day after they threatened to pull out of the ceasefire agreed with the centre in 2003.

District Magistrate GD Tripathi told: "Around 100 houses belonging to Karbi tribals were burnt down, forcing the residents to flee."

Police and paramilitary troopers were given shoot-on-sight orders to prevent further attacks.

"Strict orders were issued to the security forces to act on-the-spot," Tripathi said.