The F-15C Eagle from the 48th Fighter Wing was on a routine training mission from RAF Lakenheath when it crashed at 9:40 a.m. The cause of the crash wasn't immediately clear

LONDON: A U.S. Air Force fighter plane with one pilot on board crashed into the North Sea on Monday. The status of the pilot wasn't known.

The F-15C Eagle from the 48th Fighter Wing was on a routine training mission from RAF Lakenheath when it crashed at 9:40 a.m. The cause of the crash wasn't immediately clear.

U.K. search and rescue authorities are taking part in the search of the crash site. Coast guard officials said in a statement that they received reports the plane went down 74 nautical miles off Flamborough Head on the Yorkshire coast.

A helicopter and lifeboats have been deployed.

"Other vessels nearby are heading to the area," the coast guard said in a statement.

Lakenheath is a Royal Air Force base that hosts the U.S. Air Force's 48th Fighter Wing, known as the Liberty Wing. The base is about 80 miles (130 kilometres) northeast of London.

The wing has more than 4,500 active-duty military members.