The victims were returning after a court appearance at Kondagao when the ultras targeted the vehicle in which they were travelling, they said.
Kondagao SP Prashant Agrawal told Bhasha/PTI that the vehicle belonged to Jagdalpur central prison and the incident took place on National Highway Number 30 near Joba village.
He said that six of the victims were critically injured of whom four were policemen, one prisoner and the driver. All the injured have been shifted to hospital.