During the joint German-Soviet invasion of Poland, which started World War II in September 1939, the Luftwaffe twice bombed Modliborzyce (September 8 and 15). As a result, 87 people died and most of the buildings in the town were destroyed. The local wójt (head of the gmina) Karol Potocki was murdered by the Germans during large massacres of Poles committed in 1940 in Rury, Lublin as part pf the "AB-Aktion". In 1940 German authorities brought some 1,200 Jews from Vienna to the Modliborzyce ghetto. This group later perished – with the local Jewish population of 1,200 Jews – at Bełżec extermination camp in October and November of 1942. The Jewish community ceased to exist. Modliborzyce was one of local centers of the Home Army, and German occupation ended in July 1944.