The Maoists opened fire from a hilltop when the paramilitary men were returning from road opening duty on foot, CRPF Chief Vikram Srivastava said in New Delhi.

Acccording to preliminary information, four special police officers (SPOs) of Chhattisgarh Police along with some CRPF personnel were also injured in the attack. The condition of one of the SPOs is stated to be serious, officials said.

The troops were from the 39th battalion of the force and were a part of its 'E' and 'F' companies.

The troops were ambushed near Daurai Road area in the remote district, about 300 kms from Raipur.

This is the third major Naxal attack on the CRPF since the Maoist strike on a force contingent on April six in Dantewada killing 75 of its personnel and a Chattisgarh policeman.

On May 8, eight men of the paramilitary force were killed when naxals blew up a mine-proof vehicle also in Narayanpur district.

Chronology

Following is the chronology of major recent Naxal attacks in the country.

June 29, 2008: Maoists attack a boat on Balimela reservoir in Orissa carrying four anti -- Naxalite police officials and 60 Greyhound commandos, killing 38 troops.

July 16, 2008: 21 policemen killed when a police van is blown up in a landmine blast in Malkangiri district of Orissa.

April 13, 2009: 10 paramilitary troops killed in eastern Orissa when Maoists attack a bauxite mine in Koraput district.

April 22, 2009: Maoists hijack a train with at least 300 people on board in Jharkhand and force it to Latehar district before fleeing.

May 22, 2009: Maoists kill 16 policemen in the jungles of Gadchiroli district in Maharashtra.

June 10, 2009: Nine policemen, including CRPF troops and officers, ambushed by Maoists during a routine patrol in Saranda jungles in Jharkhand.

June 13, 2009: Naxals launch two landmine and bomb attacks in a small town close to Bokaro, killing 10 policemen and injuring several others.

June 16, 2009: Maoists kill 11 police officers in a landmine attack followed by armed assault. In a separate attack, four policemen were killed and two others seriously injured when Maoists ambush them at Beherakhand in Palamau district.

June 23, 2009: A group of motorcycle-borne armed Naxal rebels open fire on Lakhisarai district court premises in Bihar and free four of their comrades including the self-style Zonal Commander of Ranchi.

July 18, 2009: Naxalites kill a villager in Bastar and in a separate incident torch a vehicle engaged in road construction work in Bijapur district of Chhattisgarh.

July 27, 2009: Six persons killed when Naxals trigger a landmine blast at Dantewada district in Chhattisgarh.

July 31, 2009: A special police officer and another person killed by Naxals in Bijapur district.

Sep 4, 2009: Naxals kill four villagers in a forest in Aaded village in Chhattisgarh's Bijapur district.

Sep 26, 2009: Naxals kill BJP MP from Balaghat Baliram Kashyap's sons at Pairaguda village in Jagdalpur (Chhattisgarh).

Sep 30, 2009: Naxalites set ablaze Gram Panchayat offices at Korchi and Belgaon in Gadchiroli district of Maharashtra.

Oct 8, 2009: 17 policemen killed when Maoists ambushed them at Laheri police station in Gadchiroli district of Maharashtra.

Feb 15, 2010: 24 personnel of the Eastern Frontier Rifles (EFR) killed as Maoists attack their camp in Silda in West Midnapore district of West Bengal.

April 4, 2010: Maoists trigger a landmine blast killing 11 security personnel of the elite anti-naxal force Special Operations Group (SOG) in Koraput district of Orrisa.

April 6, 2010: 75 CRPF personnel and a Chhattisgarh police official killed in a naxal attack in Dantewada district.

May 8, 2010: Eight CRPF jawans were killed when Naxals blow up a bullet-proof vehicle in Bijapur district of Chhhattisgarh.

June 29, 2010: At least 26 CRPF personnel killed in a Naxal ambush in Narayanpur district of Chhattisgarh.

Source: PTI