He provided no details or did not refer to specific events, but U.N. agencies have previously accused both Congolese government forces and the rebels of recruiting children. The United Nations Human Rights Council earlier this month launched a commission that will investigate atrocities, including rapes and killings akin to “summary executions” committed by both sides since the beginning of the year.

The M23 rebels on Sunday captured Bukavu, the city of 1.3 million people, after seizing Goma, 63 miles to the north last month. At least 3,000 were reported killed and thousands displaced in the Goma fighting.

Red Cross workers clear the area in Bukavu, east Congo’s second-largest city, one day after it was taken by M23 rebels, on Feb. 17, 2025. (AP Photo/Janvier Barhahiga)

The M23 is the most prominent of more than 100 armed groups vying for control of eastern Congo’s trillions of dollars in mineral wealth that’s critical for much of the world’s technology. The rebels are supported by about 4,000 troops from neighboring Rwanda, according to U.N. experts.

Rwanda accuses Congo of enlisting Hutu fighters responsible for the 1994 genocide of minority Tutsis and moderate Hutus. M23 says it’s fighting to protect Tutsis and Congolese of Rwandan origin from discrimination and wants to transform Congo from a failed into a modern state — though critics say it’s a pretext for Rwanda’s involvement.

Unlike in 2012, when the M23 briefly seized Goma and withdrew after international pressure, analysts have said the rebels this time are eyeing political power.

The decades-long fighting has displaced more than 6 million people in the region, creating the world’s largest humanitarian crisis.

A Ugandan military official said Tuesday that Ugandan troops had entered the eastern Congolese city of Bunia to assist the Congolese army in quelling deadly violence by armed ethnic groups.