Two detonators and two packets of explosives were recovered from the spot of encounter, a place between Rahargarha and Bakrakocha villages.
Getting a tip-off about the gathering of 20 Maoists there, the security forces went to the spot, they said.
On sighting the security personnel, the ultras fired and the policemen retaliated.
After about 70 rounds were exchanged between the two sides, the rebels retreated, police said.
