British thought they needed to occupy Sudan in part because of international developments. By the early 1890s, British, French, and Belgian claims had converged at the Nile headwaters. Britain feared that the other colonial powers would take advantage of Sudan's instability to acquire territory previously annexed to Egypt. Apart from these political considerations, Britain wanted to establish control over the Nile to safeguard a planned irrigation dam at Aswan. In 1895, the British government authorized Kitchener to launch a campaign to reconquer Sudan. Britain provided men and matériel while Egypt financed the expedition. The Anglo-Egyptian Nile Expeditionary Force included 25,800 men, 8,600 of whom were British. The remainder were troops belonging to Egyptian units that included six battalions recruited in southern Sudan. An armed river flotilla escorted the force, which also had artillery support. In preparation for the attack, the British established an army headquarters at the former rail head Wadi Halfa and extended and reinforced the perimeter defenses around Sawakin. In March 1896, the campaign started as the Dongola Expedition. Despite taking the time to reconstruct Ishma'il Pasha's former gauge railway south along the east bank of the Nile, Kitchener captured the former capital of Nubia by September. The next year, the British then constructed a new rail line directly across the desert from Wadi Halfa to Abu Hamad, which they captured in the Battle of Abu Hamed on 7 August 1897. (The gauge, hastily adopted to make use of available rolling stock, meant supplies from the Egyptian network required transshipment via steamer from Asyut to Wadi Halfa. The Sudanese system retains the incompatible gauge to this day.) Anglo-Egyptian units fought a sharp action at Abu Hamad, but there was little other significant resistance until Kitchener reached Atbarah and defeated the Ansar. After this engagement, Kitchener's soldiers marched and sailed toward Omdurman, where the Khalifa made his last stand. On 2 September 1898, the Khalifa committed his 52,000-man army to a frontal assault against the Anglo-Egyptian force, which was massed on the plain outside Omdurman. The outcome was never in doubt, largely because of superior British firepower. During the five-hour battle, about 11,000 Mahdists died, whereas Anglo-Egyptian losses amounted to 48 dead and fewer than 400 wounded. Mopping-up operations required several years, but organized resistance ended when the Khalifa, who had escaped to Kordufan, died in fighting at Umm Diwaykarat in November 1899. Although the Khalifa had retained considerable