Left-wing extremists (LWE) killed at least twenty paramilitary personnel in the Jheerum area of Chhattisgarh's Jagadalpur District on Tuesday.
It is believed that the encounter between security forces and suspected Maoists, which started at approximately 10.30 a.m., lasted for about three hours.
Television reports said that the Maoist IED-cum-gunfire attack was launched on a Central Reserve Police Force (CRPF) search and patrol party.
The reports quoted unnamed intelligence sources, as saying that the Maoists had laid in wait for the patrol party in the Dharba Ghati and Tongpal areas of neighbouring Bastar District. Additional forces have been rushed to the area.
Further details of the encounter are awaited.