A briefing by Norfolk Police has just taken place and officers have said that work will continue right through the night with a view to removing the bodies of the four dead Airmen at first light.
Officers also said the undamaged helicopter, which landed to help their colleagues, has not been moved for fear that vital evidence would be disturbed.
Police also said the coast road near to the site will remain closed for several days. They have also urged the public to stay away from the area.
RAF Lakenheath said it is "truly warmed" by the messages of support following the fatal air crash of one of its military helicopters in Norfolk yesterday.
It will hold press conference on the HH-60G crash at 8am tomorrow morning.
We are truly warmed by the messages of support that have been flowing through our inboxes today. Great to have such allies! #JollyDown
The base chapel sanctuary is open 24/7 for Airmen and their families, following yesterday's tragedy. Contact the chapel with any questions.
RAF Lakenheath has reiterated that it will not release any details on the victims of last night's air crash in Cley, north Norfolk, until 24 hours after the airmen's next-of-kin have been notified.
It added that it is working on a collection for the victims' families.
We understand word spreads and gets out, but the U.S. Air Force does not release information regarding deceased airmen until after the 24hrs
We are working on a collection for the families of our fallen Airmen. Details will be released as they are finalized. #JollyDown
Aviation expert Paul Beaver has been talking to ITV News. He said "It's a very perplexing case. You have a very sophisticated helicopter with very well trained crew at the top of their game, flying on a night when the weather isn't particularly bad,
"It's blustery but not out of the limits of the helicopter, and doing something tat it was built to do which is fly at very low level at night."
He went on to say that since the Glasgow helicopter crash last month and last night's incident there have been around 90,000 helicopter flights without incident.
A colonel for the US Air Force who spent seven years flying the type of aircraft that crashed in Cley, north Norfolk, told the Eastern Daily Press that the HH-60G Pave Hawk may hold the US military's "best safety record".
– Rick Davis, a retired colonel for the US Air Force
The Pave Hawk may have the best safety record of any helicopter that the United States military has ever owned.
48th Fighter Wing commander, Col. Kyle Robinson has paid tribute to the air crew who died in a helicopter crash in Norfolk.
He said: "The loss of our Liberty Wing brethren is felt deeply across RAF Lakenheath. I can only imagine the hurt and sorrow felt by the family and friends of these Airmen. You are in our hearts and minds.
"We're already feeling a great sense of support from across the Air Force and from our UK neighbours as we go through this difficult period. Thank you for keeping our Airmen and their families in your thoughts and prayers."
Eyewitnesses Peter and Sue McKnespiey said they heard the moments just before the US Air Force Pave Hawk helicopter crashed.
"The noise was so loud it didn't seem quite right, Sue my wife looked out of the window... it was lighting the whole of the yard, it was just skimming the top of the house. We just heard a different sound of the engines and I said something's not right."
Aerial pictures show the site of the US military helicopter crash, which killed four members of the US Air Force.
The US Pave Hawk helicopter crashed while on a training exercise in Norfolk. A second helicopter - which was also on the exercise - remains at the scene after landing to help following the crash.
An eyewitness has spoken of the moment he saw a US military helicopter flying ahead of its crash in marsh land in Norfolk.