Transcript for Urgent search and rescue after US military plane collision

Now to that breaking news. At least two American Marines are found after two marine aircraft crashed into the waters off the coast of Japan last night. An urgent search and rescue mission is under way. Our chief global affairs correspondent Martha Raddatz has the very latest. Good morning, Martha. Reporter: Good morning, Michael. The marine fighter jet and the kc-130 were attempting a midair refueling. One of the most challenging maneuvers outside combat that pilots under take. This morning, rescuers battling high winds and rough seas looking for the missing Marines, the accident occurred in the middle of the night. High above the water some 200 miles off the coast of Japan. The f-18 fighter jet attempting to get fuel from the massive cc-130 like this one. The refueler has retractible hoses attached to each wing. The small jet must approach the refueler midair and plug a nozzle into the basket. But something went terribly wrong. Both aircraft ending up in the water indicating the two planes likely collided. Two Marines were in the fighter jet which was equipped with ejection seats. There were five Marines in the refueler. U.S. And Japanese ships immediately began search and rescue efforts finding those two Marines. The search goes on for the remaining five. It happened on the same day a report was released about the cause of the deadly kc-130 crash last year in Mississippi which killed 16. The cause of that was found to be poor maintenance. And military investigators are already looking to see what may have caused last night's accident, whether it was fatigue or weather. But right now the focus is on the search for those five missing Marines. Michael. All right, thank you so much, Martha.

This transcript has been automatically generated and may not be 100% accurate.