In November, a U.S. navy fighter jet crashed into the sea off Japan's southern island of Okinawa and its 2 crew members were rescued alive.
Two US Marines aircraft have been involved in a "mishap" in the skies off the coast of Japan, leaving seven US military personnel missing, officials said on Wednesday.
A total of seven personnel were believed to be on board the two aircraft, according to ABC News' Elizabeth McLaughlin. The aircraft - an F/A-18 Hornet and a KC-130 Hercules - were involved in "regularly scheduled training" at the time, and Japanese authorities immediately launched search-and-rescue aircraft afterward.
Seven missing in 'mishap' between two US marine aircraft off Japan, official says
It is unclear whether USA military officials are also assisting with the search.
"We are thankful for the Japan Maritime Self-Defense Force's efforts as they immediately responded in the search and rescue operation", it said.
The KC-130 also can be used to transport ground troops.
The McDonnell Douglas F/A-18 Hornet is a fighter and attack aircraft and can carry a wide range of missiles and bombs.
The Marines refuel aircraft differently to the Air Force, said Carl Baker, executive director of the Pacific Forum think tank in Hawaii.
However, refueling is a unsafe operation, Baker said.
The statement concluded by saying that "the investigation is ongoing" and "no other information is yet available". A series of emergency landings and parts falling from US military aircraft have highlighted safety concerns.