Dantewada (Chhattisgarh), April 13 (IANS): Four policemen were killed and seven injured on Monday when Maoists triggered a massive explosion in Chhattisgarh's Dantewada district, police said.

The terror strike took place just hours after a trooper was killed when armed Maoists attacked a BSF camp in Chhattisgarh's Kanker district.

In the latest attack, four Chhattisgarh Armed Forces (CAF) personnel were killed and seven others were wounded in the deafening blast that targeted their anti-landmine vehicle.

The attack took place at Cholnar camp of the CAF in Dantewada district, some 400 km south of state capital Raipur.

"It's a massive blast. I guess it could be about 50 kg IED (Improvised Explosive Device) used to trigger a blast near a bridge. The anti-landmine vehicle was shaken up by the blast and 4 CAF jawans succumbed to injuries," Kamal Lochan Kashyap, superintendent of police, Dantewada, told reporters at the attack site.

The policemen were returning back to the Cholnar camp after area domination drive. The injured policemen were rushed to NMDC Ltd-owned hospital at Bacheli.

Chhattisgarh has witnessed a string of attacks since April 11.