Polish independence came in November 1918 with the formation of the Second Republic of Poland. In the course of the Polish–Ukrainian War, and in the opening phase of the Polish–Soviet War, Sikorski, now a high-ranking officer of the Polish Army was involved in further operations in the Galicia region. In January 1919 he commanded troops defending Gródek Jagielloński; in March that year he commanded an infantry division, advancing to Stawczany and Zbrucz. From 1 August 1918 Sikorski commanded the Polesie Group, and the Polish 9th Infantry Division. In order to curtail excesses of the forces under his command, he oversaw trials of 36 officers. His forces took Mozyr and Kalenkowicze in March 1920, and he would command the Polesie Group during Poland's Kiev offensive in April 1920, advancing to Dniepr river and Chernobyl region. On 1 April that year he was promoted to brigade general.