A huge quantity of weapons, including AK-47 and INSAS rifles, were recovered.
Three security personnel received in the gunfight, which took place in forests near the village of Binagunda after a joint team of District Reserve Guard and Border Security Force were attacked.
Two of the three injured are from the BSF. Their condition is stable but the third personnel from the DRG is in critical care.
All three received treatment at a local hospital and would be shifted to a larger facility.
According to reports, the fighting began at around 2 PM, when a joint DRG-BSF team was conducting an anti-Maoist operation.
The DRG was set up in 2008 to combat Maoist activities in the state, and the Border Security Force has been deployed extensively in the area for counter-insurgency ops.
There was another encounter in the district last month, in which two people - a Maoist and a cop - were killed, and security forces recovered a gun, some explosives, and other incriminating materials.