At least four paramilitary personnel were injured on Thursday when Maoists opened fire on a bus, police said.
The incident took place in violence-affected Bijapur locality in thickly forested Bastar region, 545 km south of this Chhattisgarh capital.
"Fortunately, dozens of CRPF (Central Reserve Police Force) men survived when a private bus in which they were travelling to an interior belt for postings was attacked by rebels," a police officer said.
The attackers opened indiscriminate fire on the bus and then sneaked into forests when the CRPF men retaliated.
The officer added that the four CRPF men had received bullet wounds and were taken to a hospital in Jagdalpur, the Bastar district headquarters.
In another incident in Bastar region, CRPF men assisted by the state police gunned down two Maoist rebels on Thursday morning in a brief shootout.
Chhattisgarh is one of India's 13 worst Maoist-affected states and police officials say that over 400 people were killed in the state in rebel violence in 2006 so far.