KHARTOUM - An international peacekeeper was shot dead by unknown gunmen in an eastern part of Sudan's Darfur region, the joint African Union-United Nations peacekeeping mission (UNAMID) said.The killing brings the total number of peacekeepers killed in Darfur since 2007 to 44, a UNAMID spokesman said.War broke out in Darfur in 2003 when rebels took up arms against the central government, accusing Khartoum of neglecting the remote region and marginalizing its ethnic minorities.