A number of people are believed to have been killed after two US Army helicopters crashed in Kentucky.
The incident involved aircraft from the 101st Airborne Division, which said it had "resulted in several casualties".
The state's Governor, Andy Beshear, said it was "tough news" and that "fatalities are expected".
Local news reports say the incident happened at about 21:35 local time (01:35 GMT), and as many as nine people may have been killed.
It happened in the Trigg County area, close to the large Fort Campbell military base.
In a statement to the BBC, a US Army spokesperson said two HH60 Blackhawk helicopters had crashed during "a routine training mission".
"The status of the crew members are unknown at this time," they said.
"The command is currently focused on caring for the service members and their families."
Asked by the BBC if the two helicopters had crashed into each other, the spokesperson said it "was unable to confirm specifics at this time".
They added the incident was under investigation and more information would be released as it becomes available.
The 101st Airborne Division is the only air assault division in the US Army and has been sent to conflict zones internationally.