Maoists rebels set off a land mine under a truck in the central Indian state of Chhattisgarh today.
The attack killed 55 people who belonged to a government-sponsored anti-Maoist group, police said, and was one of the biggest by Maoists in recent years.
The dead were tribal members returning in trucks after attending a anti-Maoist meeting organised by the state, police said. A state government official
said 20 people had been seriously wounded and the death toll could rise.
Darmagura, 500 kilometres south of the state capital Raipur, is a stronghold of Maoists who claim to be fighting for the rights of peasants and landless labourers.
Indian Maoists, who operate in at least nine of the country's 29 states, have stepped up attacks in the past year, killing dozens of people including police.
Security analysts say New Delhi has not taken the Maoist threat in the country seriously. India's home ministry said there are about 9,300 Maoist guerrillas operating in the country