Updated

Authorities in England were working Wednesday to remove the bodies of four U.S. Air Force crewmen who died in a helicopter crash on the coast of eastern England during a training mission.

An anonymous U.S. defense official confirmed to the Associated Press that the four killed were US Air Force crew members after military officials at RAF Lakenheath confirmed to Fox News that a HH-60 Pave Hawk crashed during a training exercise mission Tuesday.

Sky News reports that the crash occurred in the Cley coastal area of Norfolk county. The incident took place on marshes, meaning it was a distance away from any populated areas.

Lt. Keenan Kunst at the Royal Air Force station in Lakenheath, Suffolk County, which hosts U.S. Air Force units and personnel, said in a telephone interview to the Associated Press that the helicopter that crashed was based there.

Police believe there is ammunition onboard the helicopter, and the military worked Wednesday with local authorities to cordon off the site and hope to remove the bodies later in the day.

"We have currently cordoned off about 500 square yards of the marshland area," said Chief Superintendent Bob Scully of Norfolk Police. "The crash site itself I would describe as an area of debris on difficult terrain on the marsh."

Local authorities are carrying out a daylight investigation, and the bodies will be removed afterward.

Pave Hawks -- a modified version of the better-known Black Hawks -- are often used for combat search and rescue missions, mainly to recover downed air crew members or other personnel during war and other hostile situations. They typically practice flying low and fast, often at altitudes of hundreds, rather than thousands, of feet.

Residents near the crash site said the helicopter sounded unusual just before the accident took place. Sue McKnespiey, who runs the Cookies crab shop in Salthouse with her husband Peter, said the helicopter came over very fast and very low.

"I don't know about engines but I am used to the sound of helicopters and this sounded very heavy and very unusual," she said. "My gut instinct was there was something wrong."

The aircraft was assigned to the 48th Fighter Wing. The names of the crew will be released after families are notified.

The Associated Press contributed to this report.