Four people have died after a US military helicopter from RAF Lakenheath crashed on the north Norfolk coast last night

A USAF Pave Hawk HH60 helicopter from RAF Lakenheath crashed at the north end of East Bank on the Norfolk Wildlife Trust Cley Marshes Nature Reserve at around 7pm on Tuesday night.

Chief Superintendent Bob Scully, from Norfolk Constabulary, told a media briefing at the Dun Cow, Salthouse, that a 400m area had been cordoned off at the site on the marsh, which lies to the west of East Bank between the A149 and the coastline, to restrict access. The cordon will remain in place today.

He said the bodies of the airmen are still on site while the coroner carries out an investigation. The US authorities will be allowed to carry out their own investigations once that has been completed, he said.

UK and US authorities were working well together and he said UK police had passed on condolences to their American counterparts.

A HH-60G Pave Hawk trains over the airfield at Lakenheath. Lakenheath aircraft are now grounded until September as part of the US Governments cost cutting along with the exception of one squadron of F-15C/D’s and HH-60G Pave Hawk helicopters which will remain combat ready. Photograph Simon Parker

The helicopter contained ammunition and he said the bullets were scattered about the site, which could prove hazardous to the public, so access was restricted. The A149 will remain closed through Cley.

Chief Superintendent Scully added: “This is difficult terrain with marshland and tides coupled with wreckage containing munitions covering a large area.

“We must undertake this investigation and recovery operation in a careful and methodical way so we can provide answers as to why this crash happened.

“For reasons of safety it is essential that members of the public adhere to the cordon. The popular activities of walking and bird-watching in this area will therefore be restricted until we have completed these tasks and ensured the marshes are safe.”

Identities of the airmen killed in the crash will be released 24 hours after next-of-kin notifications.

The aircraft, assigned to the 48th Fighter Wing, was performing a low-level training mission along the coast when the crash occurred.

A second helicopter from RAF Lakenheath was also in the area at the time of the crash and set down on the marshes to try to assist, this was within the cordon and so this aircraft remains at the scene while inquiries are ongoing.

A five-mile radius exclusion zone for any aircraft in the north Norfolk area has been put in place.

Due to the geography and the munitions from the crashed helicopter, inquiries into the cause of the collision, the recovery of the wreckage and second aircraft and an environmental assessment are expected to take a number of days to complete.

Last night people in the area spoke of their shock at the tragedy and told of hearing a “heavy and very unusual” sound overhead as the helicopter plummeted into marshland.

Peter and Sue Mcknestiey, who run Cookies Crabshop in Salthouse, heard what sounded like a helicopter and then jets flying overhead before becoming aware of fire engines, police and emergency services outside.

She said: “It just seemed an unusual thing. It didn’t seem normal because it was so low and they don’t fly low anymore.”

North Norfolk MP Norman Lamb said the crash was “utterly tragic”, adding: “My heart goes out to the families of the crew, and it is all the more difficult because I suspect the families are from a long way away and the news is just filtering through.

“It is highly traumatic too for the local communities but it was quite close to the villages and could have been even more horrific if it came down on buildings.”

Norfolk Fire and Rescue Service said six fire crews were in attendance until around 11.30pm.

A spokesman for the Royal National Lifeboat Institution said: “We were asked for three lifeboats to respond to reports that an aircraft had possibly ditched in the sea.

“Lifeboats Wells, Sheringham and Cromer were launched at the request of the coastguard but were stood down when it was confirmed that the aircraft had come down over land.”

The crash comes weeks after a police helicopter crashed into the Clutha Pub in Glasgow on November 30 2013.

Ten people were killed in the crash which happened on a busy Friday night