A landmine believed to have been planted by Maoists in the central Indian state of Chattisgarh
killed at least 12 policemen, an official said, the latest in a series of violent rebel attacks in the country.
Eleven policemen were also injured in the blast late on Saturday in Tongapal, some 500km south of the state capital Raipur, said T.J. Longkumer, an inspector general of police.
Seven of the rebels were killed in an exchange of gunfire after the blast, which hit a truck in which about 40 security personnel were travelling, he said.
Extra forces have been rushed to the site but their movements were limited in the heavily forested area, Longkumar said.
Maoists, who say they are fighting for the rights of poor farmers and landless labourers, are expanding their influence in the rural areas of east, central and southern India.
Also on Saturday, police in West Bengal state said they had regained control of a town captured by Maoist rebels in one of the most brazen attacks in recent years.
Thousands have been killed in the Maoist insurgency which began in the late 1960s and which Prime Minister Manmohan Singh has described as one of the gravest threats to India's internal security.