Raipur, July 26 - At least six troopers were injured Sunday when Maoist guerrillas triggered a landmine targeting two paramilitary vehicles in Chhattisgarh's restive Bastar region, police said.

Over two dozen Central Reserve Police Force (CRPF) troopers were in the vehicles but the landmine damaged only the front portion of one of the vehicles in Dantewada district, some 350 km south of capital Raipur, late in the evening.

'The blast was targeted for a massive casualty but only one vehicle was hit and six CRPF men injured. The jawans in the (other) vehicle fired on heavily armed guerrillas who countered the CRPF men for a while before disappearing into nearby forests under cover of darkness,' Deputy Inspector General Pawan Deo told IANS.

Police officials at Dantewada town said reinforcement of about 80-100 CRPF men besides a strong contingent of state police had reached the site. But a combing operation has been deferred till Monday morning as police suspect Maoists can ambush them if they sneak into forests in night.

The injured troopers were rushed to hospital. Forces have been put on high alert in the entire Dantewada district that has witnessed a string of deadly attacks in recent years.