Updated at 6:55 p.m. ET
The U.S. Marine Corps reports that two of its aircraft were involved in a "mishap" off the coast of Japan around 2 a.m. local time on Wednesday.
A Marine spokesman released a statement saying one of the personnel from the planes "is being evaluated by competent medical authorities." Searchers are trying to find six missing Marines.
The statement offered few details:
"The aircraft involved in the mishap, a KC-130 and an F/A-18, had launched from Marine Corps Air Station Iwakuni and were conducting regularly scheduled training when the mishap occurred.
"Japanese search and rescue aircraft immediately responded to aid in recovery.
"The circumstances of the mishap are currently under investigation."
This breaking story will be updated as new information becomes available.