Six weeks after D-Day, the Allied invasion of Normandy on 6 June 1944, the German Army was in turmoil. The Allied Army had experienced severe resistance from the German Army in Normandy. Caen was expected to be liberated by British forces immediately after the invasion but would take nearly two months to liberate. Similarly, St Lo was anticipated to be in US control by the second day of the invasion. The German forces fought furiously and US forces did not liberate St Lo until following the British liberation of Caen. However, the German Army had been expending irreplaceable resources in the attempt to defend the Normandy frontline. Also, the Allied air forces had air superiority up to 100 km behind enemy lines. Allied forces continuously bombed and strafed vital German logistical lines that provided reinforcements and supplies, such as fuel and ammunition. On the Eastern Front, the Soviet Union's Operation Bagration and the Lvov–Sandomierz Offensive were in the midst of destroying the German Army Group Centre. In France, the German Army had used its available reserves (especially its armour reserves) to buttress the front lines around Caen, and there were few additional troops available to create successive lines of defence. To make matters worse, the 20 July plot—in which officers of the German Army, including some stationed in France, tried to assassinate Adolf Hitler and seize power—had failed, and in its aftermath there was very little trust between Hitler and his generals.