DHAKA: Four people were killed when a US air force (USAF) helicopter crashed during a "low-level" training exercise.
The aircraft came down in Cley next the Sea in north Norfolk. Emergency services are at the scene with a 1,200ft (400m) area cordoned off, reports BBC.
The helicopter is an HH-60G Pave Hawk, based at RAF Lakenheath in Suffolk, a spokesman for the USAF confirmed.
The aircraft usually carries a four-man crew on board, he said.
Police said residents can stay in their homes but pedestrians and motorists are being diverted away as there is live ammunition on board.
An RAF Lakenheath spokesman said: "The aircraft, assigned to the 48th Fighter Wing, was on a low-level training mission when the crash occurred."
Six appliances from Norfolk Fire Service attended.
The helicopter came down at 18:00 GMT and a spokesman said the first unit arrived at the scene at 19:53 GMT.
Richard Kelham, chairman of Cley Parish Council, said the helicopter had crashed in the middle of Cley Marshes, a bird reserve.
BDST: 1040 HRS, JAN 08, 2014
MR/RS