The government will order an NIA probe into the Chhattisgarh killings on Saturday. Investigators will visit the state today, says Home Secretary R K Singh.

Heavily-armed Maoists had on Saturday ambushed a convoy of Congress leaders in Chhattisgarh's Bastar district, killing 27 people including Congress leader Mahendra Karma, PCC chief Nand Kumar Patel, his son Dinesh and ex-MLA Uday Mudliyar and injuring 32 others, including former union minister VC Shukla.

A survivor, Dr Shiv Narayan said nearly 20 vehicles in the convoy came under attack. "The naxals were checking almost every vehicle after the bloodbath.'

The attack took place around 4pm, but security forces could reach the spot only after 9pm.

Locals and some mediapersons helped the survivors reach Darbha police station on Saturday. From there they were taken to Maharani hospital in Jagdalpur by ambulance.

The toll in the deadly attack by suspected Maoists on a convoy of Congress leaders in Chhattisgarh rose to 27 after the bullet-riddled bodies of state party chief Nand Kumar Patel, his son Dinesh and eight others were found on Sunday.

The bodies were lying in the forested Jiram valley of Bastar region, about a km from the spot where the rebels had ambushed the convoy around 5pm on Saturday, the police said.