ADF attacks have killed dozens of people in several villages in North Kivu in recent days. Congolese authorities say people have been slaughtered with guns, knives and machetes.

Aamaq, a news agency linked to the Islamic State group, posted a statement on Saturday in which IS claimed responsibility for killing more than 35 “Christians” and wounding dozens last week in eastern Congo.

The conflict in eastern Congo has been going on for decades, with more than 120 armed groups fighting for power, influence and resources, and some to protect their communities. The ADF has been largely active in North Kivu province, but has recently expanded its activities into neighboring Ituri province.

Attempts to stop the violence have yielded little. A nearly year-long joint operation by the armies of Uganda and Congo has failed to defeat or substantially weaken allied democratic forces, a panel of UN experts concluded in a December report.

The UN and human rights organizations have accused the ADF rebels of mutilating, raping and kidnapping civilians, including children. Earlier this month, the United States offered a reward of up to $5 million for information leading to the arrest of the group’s leader, Seka Musa Baluku.