A suspected landmine blast in the central Indian state of Chhattisgarh has killed 24 paramilitary police, media reports and officials say.
Ministers said Maoist rebels were suspected of carrying out the attack.
The mine was triggered as the soldiers' armoured truck passed by on Saturday evening in Dantewada district, 1,000km (625 miles) south-east of Delhi.
Thousands have died in a three-decade Maoist insurgency across a number of central and eastern Indian states.
At least three more members of the Central Reserve Police Force were hurt in the explosion in the heavily forested district, about 500km (300 miles) south of the state capital, Raipur.
Police said the explosive device was placed in a culvert in a remote district known to be a Maoist stronghold.
No one has yet said they carried out the attack.
Ram Vichar Netam, the state's home minister, said: "The blast was powerful enough to lift the truck several feet in the air and split it into two."
Chief Minister Raman Singh said he believed the bomb had been triggered by Maoist rebels.
Maoists want communist rule across a number of states
The rebels are pressing for the creation of a communist state comprising tribal areas in the states of Andhra Pradesh, Maharashtra, Orissa, Bihar and Chhattisgarh.
They say their aim is to improve the economic and social rights of the poor and indigenous tribes.
The BBC's Sanjeev Srivastava in Delhi says federal authorities believe there may be 10,000 armed Maoist rebels in the country.
He says Delhi fears Indian Maoists may join hands with communist rebels in Nepal, who are fighting to overthrow the monarchy there.
Last month, suspected Maoists killed nine officials in India's Andhra Pradesh state.
The attack led the state government to re-impose a ban on the Communist Party of India (Maoist).
Federal junior home minister Shriprakash Jaiswal said the latest attack was "a blow to Chhattisgarh because the Maoist situation was improving when the incident happened".
Mr Jaiswal said the central government had urged states to address social and economic matters to tackle the insurgency-hit areas.