The shooting began at 11:00 a.m. local time (08:00 GMT), the radio reported, citing the chief of the local university hospital center.
Angry residents of Ikongo wanted to take justice into their own hands and lynch four individuals that were suspected of involvement in the kidnapping of an albino child, Ikongo deputy Jean Brunelle was cited as saying by the radio station. The individuals were arrested by the local gendarmerie a week earlier.
The police reportedly opened fire against the crowd that was trying to break into Ikongo's prison.
The kidnapping reportedly occurred last week. No further details were immediately available.