Forty-two bodies, including 12 women and six children, were found buried in the village of Nyamamba, in Ituri province. The bodies of seven men were found in the village of Mbogi, about 30 km east of the provincial capital Bunia, the U.N. peacekeeping mission, MONUSCO, said on Twitter.
"MONUSCO strongly condemns these barbaric and cowardly killings attributed to CODECO," it said, adding that peacekeepers had launched a patrol in the area over the weekend after hearing about attacks.
CODECO is one of dozens of militias operating in eastern Congo. Its ranks are drawn mainly from the ethnic Lendu farming community, which carries out regular attacks on Hema herders in Ituri province.
CODECO, which is split into factions and operates in remote areas, does not have a spokesperson and could not be reached for comment.
At least 195 civilians were killed and 84 kidnapped in attacks attributed to CODECO and a rival militia called Zaire since the start of December, increasing the number of displaced people in Ituri province to more than 1.5 million, the U.N. mission said.
DRC's government spokesman did not immediately respond to a request for comment.