Just before the World War II, in 1938 Strokach became a commander of the 25th Border Detachment in Tiraspol. Following the Soviet occupation of Bessarabia and Northern Bukovina, the detachment's headquarters was relocated to Kahul in 1940. In 1941–1946 Strokach was a deputy people's commissar of Interior of UkrSSR. Soon after the Nazi Germany invasion of the Soviet Union, in 1942 he was placed in charge of the Ukrainian Staff Directorate of Partizan movement. Same year Strokach became a member of underground Central Committee of the Communist Party of Ukraine. After liberation of Ukraine, in 1944 he was placed in charge of the Directorate in combating banditry.