The attack at Kalapathar area of south Bastar region had started around 1 pm. The Maoists had first sent locals to find out the position of the CRPF, a survivor, Sher Mohammad, told the media.

"We were set upon by 300 of them... villagers, women and the militia-types in black uniforms. They carried automatic weapons, AK 47, INSAS rifles," he said.

The six injured jawans in the Sukma attack have been air-lifted and sent to Raipur for treatment. Some of them are said to be critical. One of the injured men succumbed to injuries while being evacuated by air.

"We are yet to account for all the personnel and a search is on. Around 7 to 8 boys are still missing," news agency Press Trust of India quoted a CRPF officer as saying.

Prime Minister Narendra Modi expressed his condolences and tweeted, "We are proud of the valour of our @crpfindia personnel. The sacrifice of the martyrs will not go in vain".

Union Home Minister Rajnath Singh said, "It is very sad incident and we take it as a challenge". The minister also tweeted to say his deputy Hansraj Ahir is going to Chhattisgarh to take stock of the situation.

After the Sukma attack, Chhattisgarh Chief Minister Raman Singh cut short his visit to Delhi and rushed back to Raipur for an emergency meeting."Our jawans will not back down," Mr Singh said. "Sukma is Naxalite bastion. This road, once built, will cripple their network."

On April 6, 2010, 76 personnel of the CRPF died in Dantewada as they were on an area domination exercise. Two months later, on June 29, 26 CRPF men were killed in Narayanpur.

On 11 March this year, 12 CRPF men were killed and four were injured in an ambush there. The forces were providing security cover for road construction on the Bheji-Gorkha-Injiram Axis area.