After disrupting the election process in Orissa's Malkangiri, Maoists fired on a CRPF and BSF joint patrol in the Naxal-hit district tonight, the police said.
Though casualty was feared in the encounter, Director General of Police MM Praharaj told PTI over phone that the police were still waiting for detailed information.
The security personnel had taken position at a nearby school, he said.
"The ultras opened fire on the patrol which was returning from Bejingabada in Kalimela area," Praharaj said.
The patrol had been sent there to guard polling stations for the first phase of the Lok Sabha elections, the DGP added.
Additional forces were despatched to the spot to counter the ultras, DIG (South-West) Sanjeeb Panda said.
Sources however, said that the patrol was surrounded by the ultras from all sides and exchange of fire was on.
Contacted, Malkangiri SP Satyabrata Bhoi could not give details about casualty as the encounter site was about 100 kms from the district headquarters.