The group had reportedly threatened Hutu villagers with a "purification" for weeks. Armed with guns and knives, the militia simultaneously raided an army outpost and a civilian camp.
An ethnic militia killed at least 34 civilians in an hour-long attack on a camp for displaced persons in eastern Democratic Republic of the Congo early Sunday morning, local authorities said.
A group from the Mai-Mai Mazembe, a Nande "self-defense" militia, attacked a military outpost while another group from the same militia raided a civilian camp in the Hutu village of Luhanga, regional administrator Joy Bokele said.
"While they were attacking the FARDC, another group was executing the population with bladed weapons or bullets," Bokele said. He added that a motive for the attack was unclear.
A local NGO said the militia had threatened the victims with a "purification" in the weeks prior if they did not leave the camp.
"The Mai-Mai Mazembe made threats against the Hutus during the week, demanding that they leave the area or risk a purge," Center for the Study of Peace, Democracy and Human Rights said in a statement.
"The militiamen were searching for members of the Hutu community and carried out a veritable carnage before proceeding to completely burn the village."
The UN peacekeeping force MONUSCO said it repelled the attack, killing one of the assailants.
It is the most deadly massacre in about a year in the province. Ethnic violence, mainly related to land disputes, has flared in the area, which has been torn apart by more than 20 years of conflict.
Years of offensives by the Congolese army and the Mai-Mai militia groups to repel Rwandan rebels (FDLR) in the southern areas of Lubero and the northern borders of Walikale left civilians of many ethnic groups displaced.
In the void left by the FDLR, tensions have risen between the Nande and Kobo groups on one side, and the Hutu on the other, who are seen as foreigners and often collaborators with the Rwandan rebels.
Perceptions of an invasion have heightened tensions as thousands of Hutus have migrated from the south to the north of the province. The influx continues as authorities closed camps for displaced people and as farmers were forced to abandon their fields to large landowners.
aw/kl (AFP, AP)