Japanese submarines and naval aircraft active near or above American South Pacific bases according to the U.S. Joint Intelligence Committee. Daily summary dated 26 May 1942

An item reported that recently Japanese submarines were sighted near American South Pacific bases probably for intelligence purposes. Japanese navy fighters bombed Allies aircraft in flight below while using small bombs. 

Source

Map Room Papers (Roosevelt Administration), 1942 - 1945. U.S. Joint Intelligence Committee. Daily summary No. 167 dated 26 May 1942