At least 19 people were killed when gunmen attacked a fish market in northeast Democratic Republic of Congo near Lake Albert, local officials said on Sunday.
No group has claimed responsibility, but the region around Ituri province has been hit in the past by intercommunal violence between militias from the Hema and Lendu communities.
The UN mission to the DRCongo, known by its initials MONUSCO, reported the attack on Friday without giving a precise death toll. It planned to send a team to the area.
The victims were fishermen and their customers, Mulindo said. The area is known as a region where Lendu militia are active.
Violence shook Ituri province, particularly Djugu, last year when militias from Hema herder communities and Lendu farmers clashed and killed more than 100 people.
More than 300,000 were displaced or forced to flee to Uganda, on the other side of Lake Albert.
Lakes in the region are also a cause of tension between DRCongo and Uganda, with claims of Congolese militia members crossing to the Ugandan side for illegal fishing, often accompanied by attacks on locals.