In February 1918, during the Russian Civil War, Zalka formed an international group of Red Guards in Khabarovsk which mainly comprised ex-prisoner Hungarians, and participated in the punitive operations in Siberia against the White formations. At the end of World War I, Zalka chose to stay in Russia instead of returning to Hungary. Zalka met his Russian future wife Vera. They had one daughter, who later died due to complications from the accident at Chernobyl.