World War II, was in part mounted from the province's soil. General Guderian's 19th army corps attacked from the Schlochau and Preußisch Friedland areas, which since 1938 belonged to the province ("Grenzmark Posen-Westpreußen"). According to Kozłowski & Krzywicki (1988), around 56,000 Polish POWs were located in Pomerania after the invasion, and soon Germany stripped them of their status (against international law) turning them into forced labourers;in April 1940 they were 82.417 of them in Pomerania, with the number reaching 116.330 Polish forced labourers in 1944 September Because the invasion of Poland (and later the Soviet Union) was a success and the battle front moved far more east (Blitzkrieg), the province was not the site of battles in the first years of the war. Since 1943, the province became a target of allied air raids. The first attack was launched against Stettin on April 21, 1943, and left 400 dead. On August 17/18, the British RAF launched an attack on Peenemünde, where Wernher von Braun and his staff had developed and tested the world's first ballistic missiles. In October, Anklam was a target. Throughout 1944 and early 1945, Stettin's industrial and residential areas were targets of air raids. Stralsund was a target in October 1944. Despite these raids, the province was regarded "safe" compared to other areas of the Third Reich, and thus became a shelter for evacuees primarily from hard-hit Berlin and the West German industrial centers. The Pomeranian Wall was renovated in the summer of 1944, and in the fall all men between sixteen and sixty years of age who had not yet been drafted were enrolled into Volkssturm units. The province of Pomerania became a battlefield on January 26, 1945, when in the beginning of the Red Army's East Pomeranian Offensive Soviet tanks entered the province near Schneidemühl, which surrendered on February 13. East Pomeranian Offensive On February 14, the remnants of German Army Group Vistula () had managed to set up a frontline roughly at the province's southern frontier, and launched a counterattack (Operation Solstice, "Sonnenwende") on February 15, that however stalled already on February 18. On February 24, the Second Belorussian Front launched the East Pomeranian Offensive and despite heavy resistance primarily in the Rummelsburg area took eastern Farther Pomerania until March 10. On March 1, the First Belorussian Front had launched an offensive from the Stargard and Märkisch Friedland area and succeeded in taking northwestern