The Allied Democratic Forces (ADF), a jihadist group originally from Uganda, has killed more than 100 civilians in near-daily raids since late October when the army launched a large operation against them.
On Thursday afternoon the rebels killed 14 people in Mantumbi, a village 17 km (11 miles) west of the city of Oicha, said Donat Kibwana, administrator of Beni territory.
Earlier that day they had killed two and beheaded a third in Kolokoko, a suburb of Oicha, he told Reuters.
"Everybody has fled the village (Mantumbi). There are only soldiers here, who are in the process of helping to remove the bodies of the people who were all killed with knives," he said.
The U.N. says deteriorating security in the region may reverse recent progress made combating the Ebola outbreak, which has infected 3,313 and killed 2,203 people since August 2018.Aid groups suspended operations and withdraw staff from the epidemic's last strongholds following attacks on their facilities by a different rebel group late last month.