marine planes
Search and rescue operations are underway off the coast of Japan for a U.S. Marine Corps KC-130 refueling tanker and an F/A-18 fighter jet involved in a mishap, according to the Marines.

"The aircraft involved in the mishap had launched from Marine Corps Air Station Iwakuni and were conducting regularly scheduled training when the mishap occurred," according to a Marine Corps Base Camp Butler statement on Wednesday.

There were five personnel on board the KC-130 and two on board the F/A-18, a Marine official told ABC News. The incident occurred about 2 a.m. Thursday off Japan, or about noon Wednesday, Eastern Standard Time.

Japanese Maritime Self Defense Forces are leading search and rescue efforts.

The circumstances of the mishap were under investigation and no other information was available, according to the statement.

The last major U.S. military aircraft incident occurred in May when an Air National Guard C-130 cargo plane crashed outside Savannah, killing all nine personnel on board. A recent investigation determined that crash was due in part to pilot error.