Allied shipping in British Indies area threatened by Japanese forces according to the U.S. Joint Intelligence Committee. Daily summary dated 30 March 1942

An item reported that a four motored bomber attacked on 28 March a British merchant ship on a distance of 160 nautical miles south east of Calcutta, British Indies. The J.I.C. commented that the commander of the Japanese Combined Air Force (Navy) now based at Moulmein, Burma ordered an offensive apparently including attack Allied shipping by aircraft but probably also by submarines. Allied aircraft sighted a Japanese naval force including 4 cruisers, 5 destroyers, 4 transports and 2 supply ships off the Andaman Islands.

Source

Map Room Papers (Roosevelt Administration), 1942 - 1945. U.S. Joint Intelligence Committee. Daily summary No. 110 dated 30 March 1942.