Unidentified assailants attacked the village of Kimpasi, in Kwilu province's Bagata territory, on Friday, according to the territory's administrator Amedee Bangambuma.
They first killed 12 people with machetes and then a local administrative official who came to investigate the situation, Bangambuma said.
On Monday, militants also killed Kimpasi's village chief, he said, adding that all the victims were members of the Teke community.
Western DRC has seen fighting between Teke and Yaka communities since June, in a conflict first sparked by a dispute over taxes and land.
Members of the Teke community consider themselves the original inhabitants of villages spread over 200 kilometers along the Congo River. Yaka people settled in the area after the Teke.
AFP was unable to confirm the details of the attacks.
The Democratic Republic of Congo's government has said 180 people have been killed in the conflict, although that death toll is considered by aid groups to be conservative.
Tens of thousands of people have also fled their villages, according to the United Nations.
Western DRC Suffers Attacks
FILE: A volunteer brings daily food rations for internally displaced persons (IDPs), at a camp for IDPs fleeing the conflict in the DRC's Kasai province, June 7, 2017, in Kikwit, DRC.
KIKWIT , DRC - Fourteen people have been killed in western Democratic Republic of Congo, including 12 villagers hacked to death with machetes, a local official said on Monday.