Being a member of the Mensheviks and in opposition to Bolshevism, Vostretsov was arrested for a short period and barely avoided execution.

[1] In 1919–1920, he commanded the 242nd Volga Regiment of the 27th Rifle Division on the Eastern and Western Fronts, distinguished himself at the capture of Chelyabinsk, Omsk, and Minsk.

In 1921, he became the head of the Department of the Cheka troops for the protection of the borders of Siberia and in 1922 he commanded a group of troops of the People's Revolutionary Army of the Far Eastern Republic during the storming of Spasska and the expulsion of the White Guards from Primorye In 1923, he led the expeditionary force during the liquidation of general Pepyalyaev's detachment in the Okhotsk - Ayan region (Okhotsk-Ayan operation).

From October to November 1923, he served as commander of the 84th Tula Rifle Division, after which, at his personal request, he was sent to the Military Academic Courses, which he successfully completed on July 27, 1924.

During the period of preparation for military operations on the Chinese Eastern Railway (CER), the Trans-Baikal Group of Forces was created as part of the Special Far Eastern Army (ODVA), which included the administration of the 18th Rifle Corps.