Breaking News Emails

Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.
 / Updated 

Significant amounts of "hazardous" ammunition were strewn across an area the size of a soccer field where a U.S. military helicopter crashed, killing four American airmen, British police warned Wednesday.

Cordoning off a vaste swathe of a nature reserve on the east of England, investigators continued to examine the wreckage for clues as to why the Air Force HH-60 Pave-Hawk chopper - a modified version of the Army's Black Hawk - went down on Tuesday when it was practicing flying at low altitudes.

Chief Bob Scully of Norfolk Police said investigators were working with members of the British Royal Air Force (RAF) and the United States Air Force to establish the cause of the crash.

He added that an area the size of a soccer field had been cordoned off from locals because the crashed aircraft had strewn live ammunition across the crash site on impact.

"Bullets are scattered about the area of the site," he said. "So that is hazardous to members of the public."

The bodies remained at the scene early Wednesday because the British coroner needed to conduct a daylight assessment of the scene and would be removed as soon as possible, Scully said.

They will then pass the management of the scene to the air investigation branches of the U.K. and U.S, military for a more technical investigation, Scully said.

The names of the airmen killed in the crash will be released 24 hours after the airmen's next of kin have been notified, a spokesman for the 48th Fighter Wing said in a separate statement.