Despite Iran's neutrality during World War I, the Ottoman, Russian and British empires occupied the territory of western Iran and fought the Persian Campaign before fully withdrawing their forces in 1921. At least 2 million Persian civilians died either directly in the fighting, the Ottoman perpetrated anti-Christian genocides or the war-induced famine of 1917-1919. A large number of Iranian Assyrian and Iranian Armenian Christians, as well as those Muslims who tried to protect them, were victims of mass murders committed by the invading Ottoman troops, notably in and around Khoy, Maku, Salmas, and Urmia.