"We were attacked last night in the village of Mukungwe in Beni territory. It is the Allied Democratic Forces [ADFs] who stormed the village," said Eugene Matsozi, the customary chief of the area.
Authorities blamed the killings on the ADF, a Ugandan armed group based in eastern Congo that has pledged allegiance to Islamic State and wages frequent attacks.
"So far we have buried 24 people," he said.
Colonel Charles Omeonga, the military administrator of Beni territory, said "around 20" villagers were killed but that he was waiting for a final assessment.
Troops are in pursuit of the attackers, he added.
Beni territory is in North Kivu province, one of two conflict-hit provinces where Congo replaced civilian authorities with military administrations more than a year ago in an attempt to stem the bloodshed.
DRC's army blamed the ADF for killing 14 people in a church bombing in North Kivu province last Sunday, for which Islamic State claimed responsibility.
