Fourteen United Nations peacekeepers have been killed and more than 40 were wounded in an attack in eastern Democratic Republic of Congo, UN officials said on Friday, speaking on the condition of anonymity.

Jean-Pierre Lacroix, the UN's Under-Secretary-General for Peacekeeping Operations, said he was “outraged” by the attack Thursday evening in North Kivu province. He said on Twitter that medical evacuations were ongoing from the scene. He did not identify the attackers.

The UN peacekeeping mission in Congo is the largest and most expensive in the world and is aimed at calming a number of armed groups in the vast, mineral-rich Central African nation.

Radio Okapi, which is linked to the peacekeeping mission known as MONUSCO, reported that peacekeepers on Thursday repelled an attack by fighters with the Allied Democratic Forces rebel group on a U.N. base in the Beni area. The base is home to the peacekeeping mission's rapid intervention force, which has a rare mandate to go on the offensive.

The radio station, citing military sources, said fighting lasted four hours. It reported that Congolese forces did not intervene because the closest ones were several miles away.

source: Alarabiya