The jet took off from RAF Lakenheath, an American base in the UK.
A U.S. Air Force pilot has died after a fighter jet crashed into the North Sea on Monday morning.
In a statement on social media, RAF Lakenheath confirmed that "the pilot of a downed F-15C Eagle from the 48th Fighter Wing has been located, and confirmed deceased".
"This is a tragic loss for the 48th Fighter Wing community, and our deepest condolences go out to the pilot's family and the 493rd Fighter Squadron," it added.
The name of the pilot is for now being withheld until next of kin have been informed.
The incident occurred in the morning during a "routine training mission" and British search and Rescue vessels were swiftly dispatched the crash site, authorities had said in an earlier statement.
Based in Suffolk, eastern England, RAF Lakenheath has been a U.S. base since the end of World War II and is home to some 6,000 American personnel.
The $30 million F-15C is one of the most advanced tactical fighter jets in the U.S. arsenal and has been used in conflicts ranging from Operation Desert Storm in 1991 to the invasions of Iraq and Afghanistan.