A peacekeeper serving with the joint U.N.-African Union force in Darfur opened fire on fellow peacekeepers, killing four and injuring one, the United Nations said.
Kieran Dwyer, spokesman for the UN peacekeeping force, said the peacekeeping mission in Darfur, known as UNAMID, is investigating the shooting.
He said there were no further details of the so-called "blue-on-blue" incident that took place Thursday at a peacekeeping site in Mukjar in West Darfur. It was unclear whether the peacekeeper who opened fire was alive, dead or injured.
More than 300,000 people have been killed in the Darfur conflict since rebels took up arms against the Sudanese government nearly 10 years ago, accusing it of discrimination and neglect. Violence has tapered off, but clashes continue.
UNAMID was established in July 2007 and given a key mandate of protecting civilians in Darfur, but it also contributes to security for those providing humanitarian aid, verifying agreements, political reconciliation efforts and promoting human rights. It currently has about 16,500 troops and military observers and over 5,000 international police.