The governor of Kentucky has declared that fatalities are expected after two US Army Black Hawk helicopters crashed during a routine training mission.

The status of the crew members was not immediately known, the US Army’s Fort Campbell military establishment said in a statement to Reuters, without providing the number of people on board.

“We have tough news, with the first reports of a helicopter crash, and fatalities expected,” Governor Andy Beshear said in a tweet, adding that local authorities and emergency services were responding to the incident.

The crew were flying two HH-60 Black Hawk helicopters, operated by the 101st Airborne Division, which crashed around 10 p.m. Wednesday in Trigg County, the Fort Campbell public affairs office reported.

“Command is currently focused on caring for service members and their families,” the statement said, adding that the cause of the accident was under investigation.

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