The leader of Iraq's Kurdish region warned Tuesday of a "real civil war" if the central government does not implement a constitutional clause on the future of Kirkuk, the oil-rich city claimed by the Kurds. Control over Kirkuk and the surrounding oil wealth is in dispute among the city's Kurdish, Arab and ethnic Turkish populations. Nationally, the dispute pits the Kurds, who want to annex it to their autonomous region in northern Iraq, against the country's Arab majority and its small minority of Turks, known locally as Turkomen.