 After the conclusion of the September Campaign, he went to Warsaw to take up underground work with the Service for Polish Victory ("Służba Zwycięstwu Polski"), then with the Union for Armed Resistance ("Związek Walki Zbrojnej", or "ZWZ") and the Home Army ("Armia Krajowa", or "AK").From July 1940 to April 1941 he commanded the Lublin "ZWZ" district.As the local "Gestapo" were closing in, he returned to Warsaw and accepted the post of chief of staff of "ZWZ" (July 1941).