AlHijjah 03, 1433, October 19, 2012, SPA -- The U.N. human rights office demanded Friday that Sudan investigate the killing of five U.N. peacekeepers, including an attack with mortar fire and automatic weapons on a convoy heading to a village to check out reports of a massacre of 70 civilians, AP reported. U.N. High Commissioner for Human Rights Navi Pillay's office said Sudan "must promptly launch a serious investigation with a view to bringing the perpetrators to justice" in Wednesday's killing of a South African U.N. peacekeeper in the convoy attack and the Oct. 2 killing of four Nigerian peacekeepers in an ambush in Sudan's restive West Darfur region. The convoy was attacked while going to North Darfur to investigate the civilian killings and Sudan must investigate the killings of the five peacekeepers because it is responsible for protecting the African Union-U.N. mission's staff, Pillay's spokeswoman, Ravina Shamdasani, told reporters Friday in Geneva. Three others were injured in Wednesday's attack. Earlier this month the four Nigerian peacekeepers were killed and eight wounded in an ambush in El-Geneina, in West Darfur. 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 remain a target.