A US Air Force Pave Hawk helicopter crashed in the coastal marshes of eastern England during a training mission on Tuesday night, killing all four crew members aboard, officials said.
The helicopter crashed at about 6 pm local time near Salthouse on the Norfolk coast, a statement from the US Air Force said. The aircraft was based at the nearby Royal Air Force station in Lakenheath, Suffolk County.
The helicopter, assigned to the 48th Fighter Wing, was flying low at the time of the crash, the statement added.
In Washington, a US defence official said the accident killed the four US Air Force crew members aboard.
Local police in Norfolk County also said they believed all four crew had died. It said family members will be notified before details of the victims can be released.
Police in Norfolk County said they believe there is ammunition onboard the helicopter, and the scene was cordoned off so that experts could ensure the area is safe. Apart from the crew, nobody was put in any danger, police said.
It is not yet known what caused the accident.