The exchange of fire took place when a police team was conducting a combing operation inside Banjipali forest following intelligence input about presence of Maoists in the jungle, they said.
As the ultras fled from the scene and disappeared into dense forest after the gunbattle, their camp was destroyed by the police, they said.
Some Maoists were believed to have been injured in the encounter.
Some explosive materials including gelatine sticks, detonators and tiffin bombs were recovered from the site after the encounter. Other materials including tents and naxal literature were also seized, they said.
A massive combing operation and patrolling had been launched by the security forces in the area after the encounter.