Maoist rebels ambushed and killed 75 policemen in the jungles of central India yesterday in the worst ever massacre of security forces by the left-wing extremists, officials said.

A patrol from the Central Reserve Police Force (CRPF) was attacked at dawn in the state of Chhattisgarh and when reinforcements rushed to the scene they were surrounded by hundreds of heavily-armed rebels.

In a hail of automatic gunfire and landmine explosions, 75 officers were killed, seven were injured and a heavily armoured anti-mine vehicle sent to retrieve the wounded was blown up, government officials and police said.

Home Minister P. Chidambaram expressed shock at the bloodbath in the Maoist stronghold of Dantewada district and said the men had "walked into a trap."

"This shows the savage nature of the Maoists - the brutality and savagery which they are capable of," Chidambaram told reporters in New Delhi.

Home Secretary Gopal Pillai said the death toll was 75 and seven injured. A spokesman for the CRPF said this included 74 paramilitary forces and a local policeman.