By the spring of 1942, despite the failure of Operation Barbarossa to decisively defeat the Soviet Union in a single campaign, the Wehrmacht had captured vast expanses of territory, including Ukraine, Belarus, and the Baltic republics. Elsewhere, the war had been progressing well: the U-boat offensive in the Atlantic had been very successful and Erwin Rommel had just captured Tobruk. In the east, the Germans had stabilised a front running from Leningrad south to Rostov, with a number of minor salients. Hitler was confident that he could break the Red Army despite the heavy German losses west of Moscow in winter 1941–42, because Army Group Centre ("Heeresgruppe Mitte") had been unable to engage 65% of its infantry, which had meanwhile been rested and re-equipped. Neither Army Group North nor Army Group South had been particularly hard pressed over the winter. Stalin was expecting the main thrust of the German summer attacks to be directed against Moscow again.