NEW DELHI (AP) — Maoist rebels set off a land mine targeting a security patrol in central India early Thursday, killing three policemen, an official said.

The rebels blew up a vehicle used by the police on their patrol in remote Gadchiroli district of Maharashtra state soon after dawn, Inspector Manoj Babar said.

The three men died instantly. Babar said no other injuries were reported immediately.

More troops were sent to the dense forest where many rebel camps are located.

The rebels claim inspiration from Chinese revolutionary leader Mao Zedong. They have been fighting the government for more than four decades, demanding land and jobs for tenant farmers and the poor.

The rebels are in 20 out of India's 28 states.

Prime Minister Manmohan Singh has said the rebels are India's biggest internal threat.