Updated

A military officer in South Sudan said about 12 people were killed and dozens injured when an angry mob of armed youths stormed a U.N. compound and attacked civilians from a minority ethnic group.

In a statement released Thursday night, the U.N. mission in South Sudan condemned the "unprovoked attack" and called for a full investigation into the "heinous murders."

U.N peacekeepers opened fire to repel the attackers, who forced their way into a camp protecting close to 5,000 ethnic Nuers who have sought safety in the base since fighting in South Sudan broke out in mid-December.

Maj. Major Kuol Mayen Deng of South Sudan's military said that Ugandan troops stationed in the region are now protecting the U.N. base. Deng said at least 12 people were killed.