During World War I, the Ottoman Empire entered the conflict on the side of Germany and the Austro-Hungarian Empire. It ultimately suffered defeat and loss of control of the entire Near East to the British Empire and French Empire. During the conflict, genocide against indigenous Christian peoples was carried out by the Ottomans and their allies in the form of the Armenian genocide and Assyrian genocide, of which Deir ez-Zor, in Ottoman Syria, was the final destination of these death marches. In the midst of World War I, two Allied diplomats (Frenchman François Georges-Picot and Briton Mark Sykes) secretly agreed on the post-war division of the Ottoman Empire into respective zones of influence in the Sykes-Picot Agreement of 1916. Initially, the two territories were separated by a border that ran in an almost straight line from Jordan to Iran. However, the discovery of oil in the region of Mosul just before the end of the war led to yet another negotiation with France in 1918 to cede this region to the British zone of influence, which was to become Iraq. The fate of the intermediate province of Zor was left unclear; its occupation by Arab nationalists resulted in its attachment to Syria. This border was recognized internationally when Syria became a League of Nations mandate in 1920 and has not changed to date.