The US military on Thursday confirmed that one marine died in a collision between two US Marine Corps aircraft off the coast of western Japan.
One other marine was found alive and was in fair condition, the marines tweeted. A search and rescue operation continues for the remaining five soldiers, according to a statement posted by the US Marine Corps on Facebook.
The warplanes involved, a KC-130 refuelling aircraft carrying five crew members and an F/A-18 jet with two on board, had taken off from Marine Corps Air Station Iwakuni, Japanese government spokesman Yasutoshi Nishimura said.
The collision occurred about 100 kilometres south of Cape Muroto on Hikoku, the Defence Ministry in Tokyo said.
The marines' statement said the mishap occurred at about 2 am on Thursday (1700 GMT Wednesday) while the aircraft were conducting routine training and aerial refuelling.
The US military ships and aircraft were supporting the search and rescue efforts, the marines said.
The Japanese Foreign Ministry has urged the commander of US Forces Japan to immediately provide information related to the accident and to investigate it.
The collision occurred less than a month after a US fighter jet went down off the southern island of Okinawa. Its two crew members were rescued.
Twelve sailors were injured in October after a US Navy MH-60 Seahawk helicopter crashed on the deck of the carrier in the Philippine Sea.
