From the very start of World War I, Iran declared neutrality. When the war erupted on a full scale, Tabriz and much of northwestern-northern Iran had already been "de facto" occupied by Russia for several years. In later years of World War I, the Ottoman troops intervened and took control of the city by defeating the Russian troops stationed there. By this time, the Ottoman army led by Enver Pasha threatened the whole Russian army in the Caucasus region. Russian troops recaptured the city from the Ottomans at a later stage of the war. By escalation of the revolution in Russia, the Russian armies in Iranian Azerbaijan were evacuated, and the actual power passed into the hands of the local committee of the democrat party, with Ismail Nawbari at its head. Following Russia's retreat, the Ottomans captured the city once again for a few months until the decisive end of the war, and retreated thereafter. After World War I, a new era in the county's history began. Reza Shah, brigadier-general of the Persian Cossack Brigade, declared himself the king of the country following a coup d'état. He started with promises of modernization programs in Iran which was concentrated on the unification of the country, under the idea of "one country, one nation". This included centralization of the power and imposing restrictions on the local culture, heritage, and language in Iranian Azerbaijan, and the city of Tabriz. The modernization and nationalization plan of Reza Shah continued until the surge of World War II.