In April, "U. S. Grant" resumed trips to Alaskan ports carrying troops from Seattle to American bases on the Alaskan mainland and in the Aleutians and continued this vital routine until the spring of 1942. The Battle of the Coral Sea during May 1942 convinced the Japanese that a thrust at Midway Island was imperative, in an attempt to draw out the American fleet - particularly the dwindling number of vital aircraft carriers. Consequently, a powerful Japanese fleet sailed for Midway, while a smaller task force headed northward for the Aleutians to launch a diversionary raid. Carrier-based planes from the carrier struck Dutch Harbor, Alaska, on 3 June, and Japanese troops occupied Attu and Kiska islands on the 7th.