Acting on a tip-off, commandos of anti-Naxal unit C-60 combed Sindesur forest area in Dhanora taluka and spotted a group of ultras who fired at them, triggering a gun battle at around 11 am, police said.
The slain policeman has been identified as constable Govinda Farkade (41) of Jairampur village of the district.
The four Naxals and two civilians killed in the encounter are yet to be identified, police said.
Search operations are still on in the forest area.
One SLR, a country-made gun, some weapons, ammunition and other Naxal-related material were recovered from the spot, police said.
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