Fourteen policemen were injured in a fierce gun-battle with Maoist in forests of Chhattisgarh's insurgency-hit Sukma district on Saturday, the police said.
Further, at least 13 security personnel were untraceable in the forests following the encounter, a senior official said.
The encounter took place around 2.30 pm near Korajguda hills in Chintagufa area when a joint team of security forces was out on an anti-Maoist operation, he said.
Personnel of the police's District Reserve Guard (DRG), Special Task Force and CoBRA (Commando Battalion for Resolute Action) had launched the operation from Chintagufa, Burkapal and Timelwada camps based on information about presence of ultras near Elmagunda, he said.
When the team was advancing through Korajguda hills near Elmagunda, located around 450 km from the state capital Raipur, firing broke out between the two sides, he said.
"Based on ground inputs, it is believed at least four to five Maoist might have been killed and an equal number injured as security forces retaliated strongly," the official said.
"Fourteen personnel sustained injuries. They have been airlifted to Raipur and admitted at a private hospital where the condition of two of them was said to be critical," an official statement said later at night.
"So far there is no report of death of any personnel in the encounter. However, at least 13 soldiers could not be contacted after the encounter. Around 150 security personnel are still out in the forest," it added.