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In the resulting Battle of Pusan Perimeter (AugustSeptember 1950), the U.S. Army withstood KPA attacks meant to capture the city at the Naktong Bulge, P'ohang-dong, and Taegu. The United States Air Force (USAF) interrupted KPA logistics with 40 daily ground support sorties that destroyed 32 bridges, halting most daytime road and rail traffic. KPA forces were forced to hide in tunnels by day and move only at night. To deny materiel to the KPA, the USAF destroyed logistics depots, petroleum refineries, and harbors, while the U.S. Navy air forces attacked transport hubs. Consequently, the over-extended KPA could not be supplied throughout the south. On 27 August, 67th Fighter Squadron aircraft mistakenly attacked facilities in Chinese territory and the Soviet Union called the UN Security Council's attention to China's complaint about the incident. The US proposed that a commission of India and Sweden determine what the US should pay in compensation but the Soviets vetoed the US proposal.

What did the US Air Force's daytime attacks cause the KPA to do?
to hide in tunnels by day and move only at night