The incident took place this morning in a forest near Bodhrajpadar village under Bhejji police station limits, Sukma Additional Superintendent of Police Neeraj Chandrakar said.
Constable Rajiv Rawat, belonging to the 219 Battalion of CRPF, and one of the two deputy commandants in the operational units have been killed. The identity of the deputy commandant is in the process of being established.
The evacuation process is on and two helicopters have been sent.
"Two of our personnel including a deputy commandant-level officer have been killed. The entire operation was being led by senior officers," CRPF Inspector General (Operations) H S Sidhu said.
Twelve security personnel, including a CRPF deputy commandant, seven other officials of the force and four state policemen, have been injured in the incident, he added.
The evacuation process is on and two helicopters have been sent to retrieve the injured jawans, ASP Chandrakar said.
A joint squad of Central Reserve Police Force (CRPF), its specialised unit Commando Battalion for Resolute Action (COBRA) and the district police personnel was engaged in an anti-Naxal operation in the region, which is around 500 km away from Raipur, for the past few days.
Maoists triggered a landmine blast and opened fire on the security personnel, Chandrakar said. Maoists retreated as the security personnel retaliated and began to encircle them.