Persecution of Serbs in the Independent State of Croatia began almost immediately after the invasion of the Kingdom of Yugoslavia by Nazi Germany. Ustasha units, administrative commissars and Ustasha youth took up residence in all Serbian Orthodox monasteries throughout Greater Croatia. The monks who had the opportunity to flee, most often fled to either Serbia (from Croatia) or to Montenegro (from Dalmatia and Bosnia and Herzegovina), and those who were caught were sent to internment camps at Jasenovac or killed on the way.