Palamau Deputy Commissioner K Srinivasan said there was information about three policemen being killed in the blast that took place on Mohuadand-Japla road. This is the first major strike this year.
Commandant of 134 Battalion of CRPF S K Linda said the IED went off when the vehicle carrying the personnel drove over the IED.
Other CRPF and district policemen were walking at a distance behind the vehicle on an anti-Naxal operation, said Linda, who had earlier put the death toll at two.
The area has been cordoned off.