Two HH-60 Black Hawk helicopters crashed in Kentucky's Trigg County during a training session leaving nine servicemen dead, the US army says.

The two HH-60 Blackhawk helicopters were a part of the 101st Airborne Division.
The two HH-60 Blackhawk helicopters were a part of the 101st Airborne Division. (AP)

Nine people have been killed in a crash of two US Army Black Hawk helicopters during a routine training mission over Kentucky, an army official said.

"Nine soldiers died in the crash", 101st Airborne Division spokesperson Lieutenant Colonel Anthony Hoefler said on Thursday.

Crew members were flying two HH-60 Black Hawk helicopters, operated by the 101st Airborne Division, which crashed at around 0200 GMT on Thursday (10:00 pm ET) in Kentucky's Trigg County, Fort Campbell's public affairs office said.

"We’ve got some tough news out of Fort Campbell, with early reports of a helicopter crash, and fatalities are expected," governor Andy Beshear said in a post on Twitter, adding that local authorities and emergency services were responding to the accident.

"The command is currently focused on caring for the servicemembers and their families," army base Fort Campbell said in a statement. 

Fort Campbell said the incident was under investigation and that "more information will be released as it becomes available."

The HH-60 is a variant of the Black Hawk helicopter designed to provide support for various military operations, including air assaults and medical evacuations, according to the army.

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Source: TRTWorld and agencies