UNITED NATIONS (Reuters) - Steffan de Mistura, who holds a Swedish passport, was appointed Wednesday as the top United Nations envoy in Iraq, replacing Pakistani Ashraf Qazi, now assigned to head U.N. operations in southern Sudan.

De Mistura, whose appointment was first leaked last month by U.S. Ambassador Zalmay Khalilzad, currently heads the U.N. Staff College in Turin, Italy. He had served in Iraq as a deputy U.N. representative in 2005-2006 and before that spent three years in southern Lebanon during his three decades with the world body in various posts.

U.N. Secretary-General Ban Ki-moon made the appointment after the Iraqi government consented to de Mistura. At the same time Khartoum accepted the low-keyed Qazi, after rejecting previous U.N. candidates to replace Jan Pronk, who was expelled from Sudan nearly a year ago for his outspoken comments, diplomats and U.N. officials said.

Khalilzad has successfully pushed for the United Nations to enlarge it staff in Iraq and assume a higher profile to seek reconciliation between warring factions and promote dialogue with neighboring countries.

De Mistura speaks some Arabic as well as Swedish, English, French, German, Italian and Spanish.

Qazi, whose appointment was announced earlier, will head the U.N. Mission in Sudan, which includes some 10,000 peacekeepers in support of an agreement that ended decades of civil war between the Arab-dominated Khartoum government and the Christian and animist south.