The attack targeted the village of Mukondi, around 30 km (19 miles) south of the city of Beni in North Kivu province, an area plagued with rebel activity, which has been under military administration since 2021 in an attempt to restore order.
Provincial governor Carly Nzanzu Kasivita said on Twitter early on Thursday that at least 36 people had been killed in the attack, which started on Wednesday evening.
The head of a local civil society group, Mumbere Limbadu Arsene, gave a provisional death toll of 44, including women, children and the elderly, and said several villagers were still missing.
"The modus operandi suggests it was the ADF because no bullets were fired," he told Reuters via telephone, adding that some victims died trapped in their homes after attackers set them alight.
The Allied Democratic Forces (ADF) often wages attacks using machetes and hatchets.