“I want to express my outrage and utter heartbreak at last night’s attack on United Nations peacekeepers in the Democratic Republic of Congo,” Mr. Guterres said. “It is another indication of the enormous sacrifices made by troop-contributing countries in the service of global peace.”
The United Nations declined to say how many militants were killed in the attack, but a spokesman for the Congolese Army in North Kivu, Capt. Mak Hazukay, said 72 rebels died.
The mission’s statement provided few details about how the attack unfolded, but it said that the United Nations and Congolese forces had been coordinating a joint response and the agency had been conducting evacuations and assessing the security situation in the area.
The United Nations Organization Stabilization Mission for the Democratic Republic of Congo, known by its acronym, Monusco, is the largest United Nations peacekeeping mission in the world, with more than 16,000 soldiers.
Jean-Pierre Lacroix, the undersecretary for peacekeeping operations, told a news conference at the United Nations that the peacekeepers had been part of what is known as the Force Intervention Brigade, whose members have the authority to shoot first and not wait to fire in self-defense.
The Allied Democratic Forces was one of many armed groups that Monusco has been fighting under its mandate to protect civilians, he said. “We are disturbing them, and they do not like it,” Mr. Lacroix said. “They are preying on the population.”
He said that he would travel to Congo in the coming days and that the United Nations was “ determined to get to the bottom” of what had happened.
According to the United Nations, by the end of 2016, 240 United Nations personnel had died in attacks over five years. Last year, 32 United Nations or United Nations-linked personnel were killed, 26 of them peacekeepers, predominantly on missions in Africa. The highest fatalities in individual attacks numbered six and five, both in Mali.
In October, the Allied Democratic Forces killed 22 people, many of them state officials, in the Beni region when they ambushed a convoy of motorcycles with machetes and guns, according to the authorities.