"One UNAMID peacekeeper has been killed after an attack by a group of armed men on a mission patrol... near Kutum, North Darfur," the UN mission said in a statement on Wednesday.
Following the ambush on Tuesday, peacekeepers exchanged fire with the attackers, one of whom was killed, but the gunmen seized a UNAMID vehicle and abducted three mission staff.
Two of the abductees were later released, but the third was found dead, UNAMID said, adding both those freed had been injured, one of them seriously.
The war-torn western region of Darfur has seen a rise in violence in recent months.
Renewed fighting between armed groups and the Sudanese army has resulted in more than 70,000 new arrivals since December at camps in Darfur set up for those fleeing their homes, according to UNAMID.
At the weekend, seven armed men reportedly entered a camp in West Darfur and starting shooting sporadically.Last month, UNAMID reported air strikes on a village in South Darfur that wounded 13 people.
The United Nations says at least 300,000 people have been killed in Darfur since non-Arab rebels first rose up against the Arab-dominated regime in Khartoum in 2003. The government puts the death toll at 10,000.