Several homes were burned down in the town of Misia in an act that took place on Wednesday, says Kwilu Province Interior Minister Jean-Claude Bwanganga.
It is a conflict between the Yaka and Teke people that is behind the unrest.
The latest fighting between the groups has been going on since June.
More than 180 people have died as a result of the conflicts, according to the central government of Congo-Kinshasa.
According to the UN, tens of thousands of people have been displaced from their homes.
The fighting between the ethnic groups broke out after a conflict involving, among other things, land rights and tax revenue.