Melkumov joined the Bolshevik Party in 1918. In January that year he took part in the suppression of the rebellion of General Alexey Kaledin in the Don region. Being in the ranks of the first "red detachments" of the Red Army, he fought in battles from the first days of the Russian Civil War. From April 1918 he was assistant chief of a cavalry detachment. In early July he took part in the suppression of the Left Socialist-Revolutionary uprising in Moscow.