The security operation was launched after the Maoists torched police camps, and drove away the police and civil administration to establish their writ in the region since last November.

Lalgarh has been on the boil since November when a landmine exploded on the route of the convoy of Chief Minister Buddhadeb Bhattacharjee and then central ministers Ram Vilas Paswan and Jitin Prasada.

Complaining of police atrocities after the blast, angry tribals backed by Maoists launched an agitation, virtually cutting off the area from the rest of West Midnapore district.

Maoists are active in areas under 21 police stations in the state's three western districts -- West Midnapore, Bankura and Purulia.