Kisielin massacre was a massacre of Polish worshipers which took place in the Volhynian village of Kisielin (Second Polish Republic until 1939), now Kysylyn, located in the Volyn Oblast, Ukraine. It took place on Sunday, July 11, 1943, when units of the Ukrainian Insurgent Army (UPA), supported by local Ukrainian peasants, surrounded Poles who had gathered for a ceremony at a local Roman-Catholic church. Around 60 to 90 persons or more, men, women and children – were ordered to take off their clothes and were then massacred by machine gun. The wounded were killed with weapons such as axes and knives.