By the end of August the KPA had been pushed beyond their limits and many of the original units were at far reduced strength and effectiveness. Logistic problems wracked the KPA, and shortages of food, weapons, equipment and replacement soldiers proved devastating for their units. However, the KPA retained high morale and enough supply to allow for another large-scale offensive. On 1 September the KPA threw their entire military into one final bid to break the Pusan Perimeter, the Great Naktong Offensive, a five-pronged simultaneous attack across the entire perimeter. The attack caught UN forces by surprise and almost overwhelmed them. KPA troops attacked Kyongju, surrounded Taegu and Ka-san, recrossed the Naktong Bulge, threatened Yongsan, and continued their attack at Masan, focusing on Nam River and Haman. However, despite their efforts, in one of the most brutal fights of the Korean War, the KPA were unsuccessful. Unable to hold their gains, the KPA retreated from the offensive a much weaker force, and vulnerable to counterattack.