checked by the Eastern Front counteroffensive, the Southern Front counteroffensive, and the defeat of the Northwestern Army. The White Movement also suffered greater losses after the Allies pulled back from northern and southern Russia. With the main base of the RSFSR secured, the Bolsheviks could now strike back, with a solid defensive position. The armies under Kolchak were eventually forced on a mass retreat eastward. Bolshevik forces advanced east, despite encountering resistance in Chita, Yakut and Mongolia. Soon the Red Army split the Don and Volunteer armies, forcing evacuations in Novorossiysk in March and the Crimea in November 1920. After that, anti-Bolshevik resistance was sporadic for several years until the collapse of the White Army in Yakutia in June 1923, but continued on in Central Asia and Khabarovsk Krai until 1934. There were an estimated 7 to 12 million casualties during the war, mostly civilians. Many pro-independence movements emerged after the break-up of the Russian Empire and fought in the war. Several parts of the former Russian Empire—Finland, Estonia, Latvia, Lithuania, and Poland—were established as sovereign states, with their own civil wars and wars of independence. The rest of the former Russian Empire was consolidated into the Soviet Union shortly afterwards. Background World War I The Russian Empire fought in World War I from 1914 alongside France and the United Kingdom (Triple Entente) against Germany, Austria-Hungary and later the Ottoman Empire (Central Powers). February Revolution The February Revolution of 1917 resulted in the abdication of Nicholas II of Russia. As a result, the Russian Provisional Government was established, and soviets, elected councils of workers, soldiers, and peasants, were organized throughout the country, leading to a situation of dual power. Russia was proclaimed a republic in September of the same year. October Revolution The Provisional Government, led by Socialist Revolutionary Party politician Alexander Kerensky, was unable to solve the most pressing issues of the country, most importantly to end the war with the Central Powers. A failed military coup by General Lavr Kornilov in September 1917 led to a surge in support for the Bolshevik party, who gained majorities in the soviets, which until then had been controlled by the Socialist Revolutionaries. Promising an end to the war and "all power to the Soviets", the Bolsheviks then ended dual power by suppressing the Provisional Government in late October, on the eve of the Second All-Russian Congress of Soviets, in what would