In pictures: Norfolk fatal US helicopter crash at Cley

Scene of HH-60G Pave Hawk helicopter crash at Cley next the Sea, Norfolk

Investigations have started into what caused a US Air Force helicopter to crash in Norfolk, killing all four people on board. The HH-60G Pave Hawk, from RAF Lakenheath, Suffolk, came down at Cley next the Sea on Tuesday night.

Scene of HH-60G Pave Hawk helicopter crash on Cley marshes, Norfolk

The aircraft, assigned to the 48th Fighter Wing, was on a low-level training mission. Debris from the crash "on difficult terrain in the marsh" is spread over an area "about the size of a football field", said Norfolk Police.

View of HH-60G Pave Hawk helicopter crash from Cley next the Sea, Norfolk

The military helicopter came down at a nature reserve in Cley next the Sea. An area is cordoned off and the A149 through Cley is closed. Members of the public are urged to avoid the area.

Aerial view of SHH-60G Pave Hawk helicopter crash site at Cley next the Sea, Norfolk

The investigation into Tuesday night's Pave Hawk crash is being hampered by the fact it was carrying munitions. Norfolk Police said they were investigating the nature of the weaponry, which may pose a risk to the public.

A Pave Hawk helicopter, military personnel and emergency services attend the scene of a helicopter crash on the coast near the village of Cley in Norfolk

A second helicopter from RAF Lakenheath was also in the area at the time of the crash and sent to the marshes to try to assist - it remains at the scene while the investigation continues.

A US military helicopter near the scene at Salthouse in Norfolk following the crash of a US Air Force HH-60G Pave Hawk helicopter during a training exercise

Military aviation analyst Roger Smith said he was "very surprised" this type of helicopter was involved in a crash. Details of the four crew members will not be released until next-of-kin have been informed, police said.

Sign outside RAF Lakenheath/Site of Cley next the Sea helicopter crash

The 48th Fighter Wing, also known as the Liberty Wing, is assigned to the United States Air Forces in Europe. In addition to HH-60G Pave Hawks, it is home to squadrons of F-15 Eagle tactical fighter planes and F-15E Strike Eagle dual-role fighters.

Equipment arrives on transport as military personnel and emergency services attend the scene at Cley next the Sea of USAF helicopter crash

Equipment arrived on American transporters at Cley next the Sea in north Norfolk as military personnel and emergency services attended the scene of the Pave Hawk helicopter crash.

Cordon in the village of Salthouse

Police have formed a cordon in the village of Salthouse as military personnel and emergency services conduct their investigations, it is expected to last throughout Wednesday.

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