The Donbas-Don operation was one of the opening campaigns of the Russian Civil War, occurring from January to February 1918 in the Donbas region of eastern Ukraine and the Don steppe of southern Russia. The White Russian general Alexey Kaledin had taken refuge in the Kuban, a stronghold for counter-revolutionary sentiment following the October Revolution of 1917, and the Volunteer Army formed an alliance with the Don Cossacks against the communists. The Bolsheviks soon advanced into the region, with Rudolf Sivers capturing Rostov-on-Don on 23 February 1918, and Yuriy Sablin taking Novocherkassk by 25 February. The Volunteer Army was forced to retreat south during its "Ice March", while the Don Cossacks retreated to the east in the "Steppe March". Kaledin shot himself on 11 February 1918 after hearing of the Whites' plans to abandon Rostov.