Crew of a suspected North Korean ship fell overboard in the Sea of Japan near Noto Peninsula, Japanese public broadcaster NHK reported on Wednesday, citing government sources.
It was not clear if the broadcaster was referring to a member of the crew, more than one member of the crew or the vessel's entire crew.
No further details were available in the NHK report.
Japan's Coast Guard could not immediately confirm the report when contacted by Reuters.
This month, Japan rescued about 60 North Korean crew members from a fishing boat that sank after it was involved in a crash with a Japanese patrol boat that was chasing it out of Japanese waters, the Coast Guard said.