The Maoists ambushed the 40-member paramilitary force between Jhiram Ghati (Bastar) and Tongpal (Sukma) a little after 10am, according to reports.
Chief minister Raman Singh has called for an emergency meeting.
"There were about 200 Maoists. Fifteen security personnel and a civilian lost their lives. Before assembly elections also the Maoists had carried out an attack. This is a challenge not just for Chhattisgarh, but for the nation, for democracy. 50-60 companies will not do, they will have to double the forces for the Lok Sabha elections.", Singh said.
Reportedly, 20 bodies have been found. The attack happened in the area close to where Congress leaders were massacred last year.
Over 150 Maoists surrounded the CRPF team, said reports. More forces have been sent to the spot.
Personnel from the CRPF 80th Battalion and Sukma police force had gone to the area to provide protection for road construction work.
Maoists oppose road construction because it enables fast movement of forces.
MHA is waiting for more details to emerge.