Altogether, eight battalions were formed, and their task was to engage the Germans in Polish countryside, especially in the Eastern Borderlands of Poland.
Members of the 1st Battalion, under Captain Ignacy Telechun (nom de guerre Toporski), after concentration in the forests north of Warsaw, headed towards northern Podlaskie, where they wanted to set a base.
On June 11, 1943, the UBK forces under Major Stanisław Pieciul (Radecki) of the 4th Battalion engaged the Germans near the village of Pawły (Bielsk County).
These heavy losses were criticized by the Home Army's headquarters, who claimed that the UBK was profusely using lives of young Polish soldiers.
On July 17, 1944, the NKVD officers invited the Polish Home Army's Vilnius Command for negotiations, arresting them immediately.