London (CNN) A U.S. military aircraft en route from Bahrain to the United States crashed Wednesday in farmland in the east of England, killing the pilot, British police and U.S. military sources said.

The plane had taken off from RAF Lakenheath in Suffolk -- a U.S. base -- and went down near the town of Ely, Cambridgeshire police said in a statement.

It is believed the pilot was the only occupant of the plane when it crashed at around 10:30 a.m. Wednesday (5:30 a.m. ET), the statement said.

The jet was an F/A-18C Hornet and belonged to Marine Attack Fighter Squadron 232, according to Marine Corps Air Station Miramar in California.

"The aircraft was transiting from Bahrain to Miramar in a flight of six aircraft when it crashed approximately six miles northwest of the airfield. The remaining five F/A-18C's safely diverted to RAF Lossiemouth.

"The United Kingdom Coast Guard is currently on the scene of the crash site and is in close coordination with U.S. military officials," the statement said.

"Our deepest condolences go out to the family and friends of the pilot. The cause of the crash is still unknown."

Emergency services are at the scene.