Attu. High-explosive bombs were also loaded on the aircraft. Six B-24 Liberator bombers from the 21st Bombardment Squadron on Shemya were scheduled to join them, but they were diverted to attack Japanese transport ships spotted by a Navy PBY aircrew. The B-25s reached Paramushiro, which they found completely socked in by clouds. Using time/distance calculations they dropped their 500-pound bombs though the clouds on what they believed were the Japanese installations, then headed back to Alexi Point and landed after nine and a half-hour, 1,000-mile flight. At the time, it was the longest B-25 Mitchell mission of the war. Meanwhile, the B-24 Liberators had attacked the transports but failed to achieve any hits. One Liberator was hit by anti-aircraft fire from the ships and managed to make a wheels-up landing on Shemya. A second attack by B-24 Liberators was launched from Alexai Point and Shemya on 18 July. They found the weather over the northern Kuriles clear with unlimited visibility. The Katkoa Naval Base; Kashiwabra Army Staging Area and a nearby airfield were attacked. However, no hits were observed on the targets. The Japanese defenses were taken by surprise, with only five Mitsubishi A6M "Zero" and a few Nakajima A6M2-N "Rufe" float plane interceptors sent up which were unable to catch the retreating B-24s. After staging though Attu and Shemya for refueling, the B-24s returned to Adak AAF. Most importantly, aerial photographs were taken over the targets which were provided to intelligence analysists. The third attack on 11 August found the Japanese defenses prepared for the American bombers. B-24s from the 404th Bombardment Squadron and B-24s from the 21st Bombardment Squadron were met by intense anti-aircraft fire when they arrived over the Kataoka Naval Base and the Kashiwabra Army Staging Area. This time numerous bomb hits were observed on both targets and many aerial photographs were taken. About 40 Zeros were launched to intercept the Americans and in a 35-minute air battle, the B-24 gunners claimed four Zeros shot down, with one probable and four possibles. The Japanese managed to shoot down one B-24. Another B-24 diverted to Soviet territory and crash-landed at the airfield at Petropavlovsk on Kamchatka Peninsula. One airman was killed in the crash and the survivors were, at least officially, interned in the Soviet Union. At the time, the Soviets were officially, for strategic reasons, neutral in the war between the Japanese Empire and Western Allies;