Communist rebels are thought to be behind the blast that took place on Thursday in the Karmapada forest of Chaibasa district, about 230km from the provincial capital of Ranchi.
The officers from the Central Reserve Police Force (CRPF) were heading back to their base after defusing landmines when their jeep struck a mine, B C Sharma, the state’s most senior police officer said.
CNN-IBN, a private television channel, quoted other police officials as saying that the CRPF personnel had gone on a long-range patrol on Wednesday, when they found landmines planted near a school.
G S Rath, the state’s additional director-general of police, said: “They called in the bomb disposal squad. Eight bombs were defused on Wednesday and the rest of them were deactivated on Thursday.
“They were returning to the district headquarters after completing the job when the blast triggered by the Maoist guerrillas took place.”
Three of the victims belonged to the bomb disposal squad.
The blast is seen as a move to avenge the arrest of two rebels in Chatra district on Wednesday.
Rebels of the Communist Party of India-Maoist have been fighting for more than 20 years, demanding land and jobs for farm workers and the poor.
The rebels often attack police and government officials, whom they accuse of colluding with landlords and rich farmers to exploit the poor.