UNITED NATIONS (AP) — A police officer from Bangladesh was killed in a gang attack at a U.N.-African Union peacekeeping mission facility in a camp for people displaced by the conflict in Sudan's western Darfur region, U.N. officials said Monday. A police colleague was injured.

U.N. deputy spokesman Eduardo del Buey said that a gang of unidentified assailants surrounded and opened fire at staff in the mission's community policing center in the Otash camp in Nyala, South Darfur, in the early morning hours on Sunday.

The gang fled after the police opened fire, he said.

The U.N. mission strongly condemned the attack, which constitutes a war crime under international law.

U.N. Secretary-General Ban Ki-moon, who is visiting South Korea, said he "deeply regrets the latest attack on peacekeepers in Darfur," according to a statement released by his spokesperson. Ban urged the government of Sudan and the U.N. mission "to conduct a full investigation into this incident."

Darfur has been torn by conflict since 2003, when rebels took up arms against the central government, accusing it of discrimination and neglect. Violence has tapered off, but clashes continue and peacekeepers are a target.