 His actions secured the nationalization of industrial centers concentrated in the eastern Ukraine.Sergeyev became one of the organizers of Ukrainian Central Military-Revolutionary Committee in resistance to Central powers and Kaledin's Cossacks.On March 27 he organized the Donetsk Army by the order of Vladimir Antonov-Ovseyenko, however by the end of April 1918 that army was integrated into the 5th Army of Red Army headed by Kliment Voroshilov.