Maoist rebels have blown up a truck in Darmagura in central India, killing at least 50 people.
Police said those killed belonged to a government-sponsored anti-Maoist group.
The incident comes on the eve of a visit to the country by US President George W Bush.
Darmagura, 500km south of the state capital, Raipur, is a stronghold of Maoists who claim to fight 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.
