In mid-August 1943 a Polish unit of the Uderzeniowe Bataliony Kadrowe (English: Striking Cadre Battalions, UBK), which was controlled by the resistance organizationKonfederacja Narodu, organized armed attack on East Prussian villages in the area of Johannisburg (now: Pisz). The attack, commanded by Colonel Stanislaw Karolkiewicz, was a revenge for German atrocities, committed in Bezirk Bialystok against Polish population. The targets of the attack included devoted Nazis, members of NSDAP and inhabitants engaging in brutality against Polish population. According to Polish sources, some 70 Germans were killed and 40 German farms were razed to the ground, while an eyewitness reports 13 killed people, including a woman and two children, and two people wounded. The revenge attack caused shock among Prussian Germans and caused them to rethink their genocidal tactics against Polish population
Following Nazi and Soviet aggression on Poland in September 1939, the Second Polish Republic was divided by the two allied powers under the terms of the Ribbentrop-Molotov pact. The area of Białystok became part of the Byelorussian Soviet Socialist Republic, and was annexed by the Soviet Union. Thousands ethnic Poles, and also Belarusians and Jews, were forcibly deported to Siberia. Among the deported Poles were civil servants, judges, police officers, professional army officers, factory owners, landlords, political activists, leaders of cultural, educational and religious organisations, and others activists in the community. All of them were dubbed enemies of the people.
Polish resistance against the Soviets in the area of Białystok (especially along the swampy Biebrza river) began immediately after the September Campaign and in mid-1940 there were conspirational organizations in 161 towns and villages in the future area of Bezirk Bialystok. Skirmishes with the NKVD were common, mostly around Jedwabne, where the anti-Soviet feelings were the strongest.