The United Nations High Commissioner for Human Rights has accused the March 23 Movement, backed by Rwanda, of killing children in Bukavu, the second-largest city in the eastern Democratic Republic of the Congo.

In a statement, Volker Turk confirmed that his office “has verified cases of children being executed” by the movement after it entered the city last week.

He also noted the presence of children carrying weapons, as the UN had previously accused both Congolese government forces and the March 23 Movement rebels of recruiting children.

The UN Human Rights Council has launched an investigation into the crimes committed by both sides, as fighting continues in the region, resulting in the deaths of 3,000 people and the displacement of thousands more.