The exchange of fire took place in the forest of Panchakudi under Kalyansinghpur police station where about 20 armed Maoists had gathered at a temporary camp, Rayagada Superintendent of Police Rajesh Pandit said.
A joint team of Special Operation Group (SOG) and District Voluntary Force (DVF) were carrying out combing operation in the forest when they spotted the ultras, he said.
As the Maoists opened fire on seeing the combing team, the security personnel retaliated and a naxal identified as Paraya Kutruka (34) was injured in the gun-battle that ensued, the SP said adding the injured ultra was arrested and shifted to district headquarters hospital here for treatment.
A massive combing operation was launched in the area after the encounter and police said some more naxals might have been injured.