RAIPUR: In the bloodiest attack on security forces, Naxals trapped and gunned down 75 personnel during a joint "Operation Green Hunt" offensive against the ultras in the thick forests of Mukrana in Dantewada district of Chhattisgarh, one of the strongholds of the Maoists .

The incident occurred between 6 am and 7 am when nearly 100 personnel comprising CRPF and state police were returning after opening a road for the troops to begin an operation against the Naxals.

While 74 of those killed were CRPF personnel, including a deputy and an assistant commandant, one was a head constable of the district police.

Dantewada Superintendent of Police Amresh Mishra said the Naxals first blew up a vehicle carrying the CRPF personnel near Chintalnar-Tarmetla village in the district.

Immediately after the blast, the CRPF personnel and a few police personnel tried to take cover when they came under heavy fire from hundreds of Naxals, well entrenched on the adjacent hillock.

The CRPF team had been camping in the interiors of Tarmetla jungles for the last three days as part of a combing operation and area domination exercise, Mishra said.

The attack shook the Centre and Prime Minister Manmohan Singh called Home Minister P Chidambaram over telephone to make an assessment of the situation. Both of them expressed shock over the attack and grief over the loss of lives.

The National Security Council met under the chairmanship of the Prime Minister and is understood to have discussed the deadliest Maoist strike. Chidambaram, some of his cabinet colleagues and the three service chiefs attended the meeting.

While the Prime Minister called it a "horrific" incident, Chidambaram said it showed the brutality and savagery of the Maoists.

Rattled by the "very high" casualty, Chidambaram said something must have gone "drastically wrong" in the joint operation as the personnel seemed to have walked into a trap.

Bodies of the 75 personnel have been recovered from the site of the attack suspected to have been carried out by about 1000 Naxals, Inspector General R K Vij said.

The Naxals had planted IEDs which blew up an anti-mine vehicle killing the lone occupant, the driver. This was followed by heavy exchange of fire between the remaining CRPF personnel and the Maoists.

Seven of the injured CRPF men have been evacuated for treatment from the forest area, he said.