 On 10 March, the invasion force was attacked by ninety United States Navy aircraft from and with "Tsugaru" suffering light damage.On 4 May "Tsugaru" was assigned to Admiral Shima’s Tulagi invasion force, which was part of “Operation Mo” (the invasion of Tulagi and Port Moresby in New Guinea).However, the invasion plans were cancelled after the Battle of the Coral Sea and "Tsugaru" was assigned instead to “Operation RY" (the invasion of Nauru and Ocean Island).