3 people are missing from the Navy aircraft that crashed into the Philippine Sea on Wednesday.
Names of the missing people are withheld until the search is over.
The C2-A Greyhound transport plane was carrying 11 crew and passengers to an aircraft carrier.
Eight people have been rescued and are in good condition aboard the carrier, the USS Ronald Reagan, the Navy said in a statement. US and Japanese ships and planes are searching the area for the three people who remain missing.
The cause of the crash wasn`t immediately known, according to an initial statement from the US Navy 7th Fleet. "I have been informed by the US military that engine trouble may have caused (the crash)," Japan`s Defense Minister Itsunori Onodera told reporters Wednesday.