At least 66 civilians have been killed in eastern Democratic Republic of Congo in one of the deadliest massacres this year, carried out by fighters linked to the Islamic State group, local officials said Saturday.

The attack happened in the Walese Vonkutu chiefdom of Irumu territory, near the border with Uganda, between Thursday and Friday. The assailants, members of the Allied Democratic Forces militia, killed the victims — including women — with machetes, according to Marcel Paluku, president of a local civil society group.

Jean Tobie Okala, spokesperson for the United Nations mission in Ituri province, described the scene as a “bloodbath.” He said the initial death toll of 31 had since climbed to 66, based on updated information from civil society networks. The number of hostages taken remains unknown.

The ADF, a Ugandan Islamist group that pledged allegiance to Islamic State in 2019, has stepped up attacks across eastern Congo in recent years, killing and abducting hundreds, including many children, according to human rights monitors and the UN.

Paluku and other officials suspect the latest attack was retaliation for intensified bombing by joint Congolese and Ugandan forces, which began Sunday.

Founded in the late 1990s, the ADF now operates across both sides of the Congo–Uganda border. It has extended its reach toward Goma, eastern Congo’s largest city, and deep into Ituri province. Muslims make up roughly 10 percent of Congo’s population, concentrated largely in the east.

The massacre comes as hopes rise for a possible end to another conflict in the region — the ongoing war with the M23 militia, which is backed by neighbouring Rwanda.

In December, ADF fighters killed at least 10 villagers and abducted several others in North Kivu province. Rights groups warn that civilians remain the primary targets of ADF violence, with little protection from overstretched government and UN forces.