The attack occurred in Bijapur district, 500km south of the state capital Raipur, Ram Vichar Netam, the Chhattisgarh state home minister, said.


Maoist rebels, who say they are fighting for the rights of neglected tribes and landless farmers, have gained control of 10 of the state's 16 impoverished districts, according to police.


As a result, about 50,000 villagers have been displaced in the state and are now living in tent shelters as Indian counter-insurgency forces operate in the countryside.


Officials have said India's Maoist insurgency, which dates back over four decades, now threatens huge swathes of India's centre, east and south.


Last year, Manmohan Singh, the Indian prime minister, described the  Maoists as the single biggest threat to the nation's internal  security.