By 5 July, forward elements of Fourth Panzer Army had reached the Don River near Voronezh and became embroiled in the battle to capture the city. Stalin and the Soviet command still expected the main German thrust in the north against Moscow, and believed the Germans would turn north after Voronezh to threaten the capital. As a result, the Soviets rushed reinforcements into the town to hold it at all costs and counterattacked the Germans' northern flank in an effort to cut off the German spearheads. 5th Tank Army, commanded by Major General A.I. Liziukov, managed to achieve some minor successes when it began its attack on 6 July, but was forced back to its starting positions by 15 July, losing about half of its tanks in the process. Although the battle was a success, Hitler and von Bock, commander of Army Group South, argued over the next steps in the operation. The heated debate, and continuing Soviet counterattacks, which tied down Fourth Panzer Army until 13 July, caused Hitler to lose his temper and dismiss von Bock on the 17th of July. As part of the second phase of the operation, on 9 July, Army Group South was split into Army Group A and Army Group B, with Wilhelm List appointed as commander of Army Group A and Army Group B commanded by Maximillian von Weichs.