LONDON (Reuters) – A U.S. fighter plane crashed off the coast of northeast England on Monday, sparking a search and rescue operation for the pilot in the North Sea.

The U.S. Air Force said the F-15C Eagle from the 48th Fighter Wing crashed at around 0940 local time (0840 GMT).

“At the time of the accident, the aircraft was on a routine training mission with one pilot on board,” it said.

“The cause of the crash as well as the status of the pilot are unknown at this time and UK Search and Rescue have been called to support.”

Representatives for the Pentagon did not immediately respond to a request for comment.

The aircraft was from RAF Lakenheath, the largest U.S. Air Force-operated base in England and the only U.S. Air Forces in Europe (USAFE) F-15 fighter wing. It is located about 25 miles (40 km) northeast of Cambridge.

In 2014, a U.S. military helicopter crashed on the coast of eastern England, killing all four crew on board.