The two nations have called off their routine joint operation to focus on the search, a Japanese navy spokesman told AFP.
However, Japan Today reported that the USA 7th Fleet said, "Multiple searches were conducted inside the ship but were unable to locate the sailor", in a statement. The destroyer is believed to have been conducting routine operations throughout the Pacific for much of this year.
Defense News first reported the missing sailor.More news: Sanders says Trump joking about police brutality
Last month, the Stethem sailed within 12 nautical miles of Triton Island, which is claimed by China, Vietnam and Taiwan as part of ongoing territorial disputes in the South China Sea. Multiple searches of the destroyer were conducted but the sailor hasn't been found.
"USS Stethem along with Japan Maritime Self Defense Force ships JS Izumo and JS Sazanami are searching the area along with helicopters from Izumo". The sailor was later found hiding on the ship. He is now reported to be facing possible discharge from the Navy, Military.com reported.
The Navy Times reports that another sailor was lost in June off the coast of North Carolina. Fire Controlman Second Class Christopher W Clavin was later presumed dead after the Navy abandoned the search operation after 76 hours.