In late 1932 Tuominen was paroled and received a letter from Kuusinen, who was then one of the Comintern's secretaries, urging him to move to the Soviet Union. Tuominen secretly went to Sweden and then, in April 1933, to the Soviet Union, where he moved into Kuusinen's apartment. He was given a crash course at the International Lenin School and was appointed General Secretary of the Finnish Communist Party, also becoming a member of the Comintern Executive Committee Presidium.