A US Navy aircraft has crashed into the Philippine Sea with 11 crew and passengers on board. In a statement, the US 7th Fleet commander says a search operation is underway involving the USS Ronald Reagan.

Eight of the missing have been found, they have been transferred to the USS Ronald Reagan and are said to be in good condition. A search is continuing for the three missing people.

The @USNavy is conducting search and rescue following aircraft crash. We are monitoring the situation. Prayers for all involved. https://t.co/1AxmegKqvu — Donald J. Trump (@realDonaldTrump) November 22, 2017

The aircraft went down southeast of Okinawa at approximately 2:45pm local time on Wednesday. The US Navy says the names of those involved are being withheld until their family and next of kin can be notified.

A family liaison center has been established at Commander, Fleet Activities Yokosuka to offer assistance to those concerned about the crew and passengers. While Japanese ships and aircraft have also joined in the search effort.

A @USNavy aircraft carrying 11 crew and passengers crashed into the ocean southeast of Okinawa while en-route to the Ronald Reagan (CVN 76). #USSRonaldReagan is conducting search and rescue operations. https://t.co/ZJqpxyYqcR — 7th Fleet (@US7thFleet) November 22, 2017

The aircraft was en route to the US Navy aircraft carrier USS Ronald Reagan (CVN 76), which is currently operating in the Philippine Sea.

The cause of the crash is not yet known. However Onodera says the crash may have been a result of engine trouble. The propeller-powered transport plane involved in Wednesday’s crash, a C-2 Greyhound, carries personnel and cargo from mainland bases to carriers at sea. In operation for more than five decades, the plane is due to be replaced by the long-range Osprey aircraft.

READ MORE: Japanese boat crashes into US Navy destroyer in Pacific Fleet’s 5th collision this year

The crash is the latest in a series of series US Navy incidents this year. Less than a week ago, a destroyer collided with a Japanese tugboat in Sagami Bay, off the east coast of Japan. In June, seven sailors were killed when the USS Fitzgerald collided with a Philippines container ship in the middle of the night southwest of Yokosuka.

The USS John S. McCain crashed into a commercial vessel in the Strait of Malacca off the coast of Singapore in August. Ten sailors drowned as seawater filled sealed compartments of the ship. In all, there have been six such incidents since the start of 2017.

Eight Navy officers, including the 7th Fleet commander, were removed from their posts over the incidents. A Naval investigation into the collisions determined that the USS Fitzgerald and McCain collisions were avoidable and resulted from poor judgment and a combination of failures by crew and command.