 Complete the following phrase:  In September 1939, after the outbreak of World War II, German Luftwaffe planes bombed Zamość several times. Over 250 people were killed, mainly civilians. The city was overrun by the Germans during the invasion of Poland and the local garrison, staffed by the Polish infantry regiment of podpułkownik Stanisław Gumowski, was defeated. On September 27, 1939, Nazi Germany signed a border treaty with the Soviet Union which had invaded Poland from the east, and, consequently, on September 28, 1939, Zamość was handed over to the Red Army  for about a week. The Soviets withdrew on October 5, 1939, along with some 5,000 Jews after a further demarcation line adjustment. The Germans returned to the city on October 8, 1939 and shortly afterwards mass arrests of prominent citizens began. This was as part of the secret 