In 1942–1943, he organized the anti-German resistance group, Union for the Liberation of Lithuania (Lithuanian: Lietuvos išlaisvinimo sąjunga), and established contacts with Polish and Jewish underground.

When Germany invaded the Soviet Union in June 1941, Vitas – unlike many other communists – remained in Lithuania and began organizing anti-German resistance.

Vitas established contacts with Lithuanian intelligentsia and various small anti-German groups in Vilnius, Šiauliai, Panevėžys, Kaunas.

[5] On 24 February 1943, he co-founded the Anti-Fascist Committee, which was renamed to the Union for the Liberation of Lithuania and which united many Lithuanian pro-communist activists.

[4] Soviet censors suppressed Vitas' biography due to his brother Ignas Valūnas who owned a restaurant in Alytus and thus was deemed a "bourgeoisie oppressor".