RAIPUR: Indian police shot dead three Maoists in separate gunbattles in central Chhattisgarh state, where security forces are engaged in an operation against the rebels, a senior officer said Sunday.

In one incident, two Maoists were killed Sunday in Bijapur district, 500 kilometres from state capital Raipur, senior police official Avinash Mohanty told AFP by phone.

A third rebel was killed and another three injured in the same district on Saturday, Mohanty added. Chhattisgarh is a known hotbed of Maoist activity with many senior guerrilla leaders believed to be based in the state's dense forests.

The Maoists have threatened to unleash a 'tornado' of violence if New Delhi goes ahead with a planned large-scale offensive against them.

Premier Manmohan Singh has described the insurgency, that began as a peasant uprising in 1967, as the single greatest threat to India's internal security. -AFP