TOKYO (Reuters) – A U.S. Navy transport plane carrying 11 people crashed in the Philippine Sea south of Japan on Wednesday as it flew to the aircraft carrier Ronald Reagan, the U.S. Seventh Fleet said.

Eight people were rescued, with three others missing, it said, adding that all of the rescued personnel were transferred to the carrier for medical evaluation and were in good condition.

“Search and rescue efforts for three personnel continue with U.S. Navy and Japan Maritime Self-Defense Force (JMSDF) ships and aircraft on scene,” the U.S. Seventh Fleet said in a news release.

“The incident will be investigated,” it added.

The plane was conducting a routine transport flight carrying passengers and cargo from Marine Corps Air Station Iwakuni to the carrier, which was operating in the Philippine Sea as part of an exercise with Japanese forces, it said.

The aircraft carrier USS Ronald Reagan steams the Philippine Sea during Annual Exercise 2017, joint military training between the U.S. Navy and the Japan Maritime Self-Defense Force, in this handout photo taken November 20, 2017. Mass Communication Specialist 2nd Class Kenneth Abbate/U.S. Navy/Handout via REUTERS

U.S. President Donald Trump was briefed on the crash at his Mar-a-Lago retreat in Florida, where he is spending the U.S. Thanksgiving holiday, said White House spokeswoman Lindsay Walters.

“The @USNavy is conducting search and rescue following aircraft crash. We are monitoring the situation. Prayers for all involved,” Trump wrote in a Twitter post.

Japanese Minister of Defence Itsunori Onodera told reporters the U.S. Navy informed him that the crash may have been a result of engine trouble.

The propeller-powered transport plane, a C-2 Greyhound, carries personnel, mail and other cargo from mainland bases to carriers operating at sea.

C-2 aircraft have been in operation for more than five decades and are due to be replaced by the long-range tilt-rotor Osprey aircraft.