(LONDON) — An American fighter jet crashed into the North Sea off the coast of England on Monday morning, killing the only pilot on board, officials said.

The F-15C Eagle, from the U.S. Air Force’s 48th Fighter Wing, was on a “routine training mission” when it went down at approximately 4:30 a.m. ET, according to Col. Will Marshall, commander of the 48th Fighter Wing.

The aircraft deployed earlier that morning from the U.K. Royal Air Force (RAF) station near the village of Lakenheath in Suffolk, England. The base hosts U.S. Air Force units and personnel.

U.K. coastguards eventually located the wreckage of the downed plane, and efforts were underway to recover it from the water on Monday evening while search and rescue crews continued looking for the pilot.

“The cause of the crash is unknown at this time,” Marshall said in a statement Monday. “We’re extremely grateful for the timely response of our U.K. counterparts in support of these recovery efforts.”

The pilot, identified as 1st Lt. Kenneth Allen, was later found and confirmed to be dead.

“We are deeply saddened by the loss of Lt. Allen, and mourn with his family and his fellow Reapers in the 493rd Fighter Squadron,” Marshall said in a statement Tuesday. “The tremendous outpouring of love and support from our communities has been a ray of light in this time of darkness.”

Allen had served with the 48th Fighter Wing at RAF Lakenheath since February. He is survived by his wife and parents.

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