Prior to the First World War, the Kurds living in a region called the Mosul wilayat were subjects, like their Arab neighbors, of the Ottoman Empire. During the war, a drastic increase in the demand for oil fostered concern among the great powers about intense post-war competition for this strategic commodity. This concern was especially acute in Britain. By the end of the war 90 percent of the British navy and a rapidly increasing portion of its merchant marine had become oil-fired. The British saw their heavy dependence on oil imports from the U.S. as a direct threat to their supremacy on the seas and ultimately to the security of their empire. Determined to control a rich source of oil, the British defeated the Kurds' struggle for national self-determination and made sure that the Mosul wilayat was included in Iraq, for which London had a League of Nations mandate. To secure this territorial arrangement, the British had to make deals and compromises with the U.S. and France. Britain and its western allies emerged as the immediate winners, and the Arabs of Iraq were well-placed to benefit in the longer run, especially after Iraq obtained its independence. The Kurds, however, have suffered terribly from the inclusion of Mosul in Iraq.