The rebels had also abducted four policemen recently. Two of them remain untraced.

Lalgarh, about 200 km west of Kolkata, has been on the boil since November last year when a landmine exploded on the route of the convoy of Chief Minister Buddhadeb Bhattacharjee and two then central ministers -- Ram Vilas Paswan and Jitin Prasada.

Alleging police atrocities after the blast, the Maoists, alongside the People's Committee Against Police Atrocities (PCAPA), launched an agitation and turned the area into a virtual 'free zone' by torching police camps and offices of the ruling communists and driving out the civil administration.

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