The security personnel were on routine combing operation in ultra-dominated pockets when the encounter took place at Nawadih, DIG (Palamau) Saket Kumar Singh said.
The encounter lasted for around 20 minutes before JJMP activists managed to flee, he said.
No casualty from the police camp was reported.
A combing operation was launched on the bordering areas of Palamau-Garwah districts following the encounter, Singh said.
