Work began in 1903 on a commercially significant line from Benguela all the way inland to the Katanga region, aiming to provide access to the sea for the richest mining district of the Belgian Congo. The line reached the Congo border in 1928. In 1914, both Angola and Mozambique had Portuguese army garrisons of around 2,000 men, African troops led by European officers. With the outbreak of World War I in 1914, Portugal sent reinforcements to both colonies, because the fighting in the neighboring German African colonies was expected to spill over the borders into its territories.