Two US Marine Corps jets have crashed off the coast of Japan while refueling during a training exercise.
At around 2am local time, Japanese search and rescue teams were launched.
The Marine Corps said a KC-130 refueling tanker and a F / A-18 jet fighter were involved in a 'mishap' during scheduled training.
The US Marine Corps said in a statement: "We are aware of an incident involving Marine Corps aircraft off the coast of Japan.
"Search and rescue operations continues for a KC-130 and an F / A-18 that was involved in a mishap off the coast of Japan around 2:00 am Dec. 6.
"The aircraft involved had been launched from Marine Corps Air Station Iwakuni and was conducting regularly scheduled training."
"Japanese search and rescue aircraft immediately responded to aid in recovery.
"The circumstances of the mishap are currently under investigation."
CBS match Mary Walsh tweeted: "A Marine F-18 & A / C-130 crashed during aerial refueling off Iwakuni, Japan." Both aircraft went into the water.
"There were five on the C-130 and two on the F-18, search and rescue is underway.
"Search & rescue operations continues for US Navy aircraft involved in mishap off the coast of Japan.
The Japanesse Maritime Self Defense Forces are leading the rescue efforts. The US Marine Corps has not formally announced how many staff have been invovled.
A marine official told ABC News there were five staff on board the KC-130 and two on board the F / A-18.