New Delhi: Four Chhattisgarh Police personnel were killed and seven injured in a heavy exchange of fire with Maoist guerillas in Narayanpur district on Wednesday morning, the Union home ministry said.

The slain police officers—two sub-inspectors and two constables — were all from the District Reserve Guard, the state force created to fight the Naxals.

With the Naxals’ Tactical Counter Offensive Campaign (TCOC) period—where they embark on an offensive against security forces—yet to begin, the state police launched an offensive against the extremists after receiving intelligence inputs of their presence in the Abhujmaad area of Naraynapur. “There was a heavy exchange of fire that lasted over an hour starting around 11am on Wednesday morning. There have been casualties on the other (Naxal) side as well. This was a very difficult terrain with dense forests and hills and the Naxals know the terrain extremely well," a senior state police officer said, requesting anonymity.

The injured officers were evacuated and taken to the state capital Raipur.