The security operation was launched in and around Lalgarh last month after Maoists torched police camps and drove away the police and civil administration.

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

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