Nine U.S. soldiers died in a tragic helicopter crash during a nighttime training mission in Kentucky.

Two Black Hawk helicopters crashed into a field around 10 p.m. Wednesday night near Fort Campbell.

It's not yet clear what caused the accident in Triggs County, or if the two helicopters collided. There were no injuries on the ground.

Nine soldiers killed

The helicopters were from the 101st Airborne Division. One of the helicopters had five passengers and the other had four, Brig. Gen. John Lubas, the 101st Airborne deputy commander, said.

“This is a truly tragic loss for our families, our division, and Fort Campbell,” Lubas said. “Our number one priority is caring for the families and soldiers ... Our thoughts and prayers are with these families and soldiers during this difficult time.”

Lubas said the helicopters were "flying a multi-ship formation, two ships, under night vision goggles at night."

Military investigators are working to determine what caused the tragedy 30 miles northwest of Fort Campbell. The helicopter came equipped with devices similar to flight recorders that could be used to reverse-engineer the crash.

"We’re hopeful that will provide quite a bit of information of what occurred,” Lubas said.

Victim identified

The victims' names have not yet been released, but one of the families identified 25-year-old Staff Sgt. Caleb Gore, 25, of Wayne County, North Carolina, as one of the casualties.

Kentucky governor Andy Beshear (D) issued a statement of support for the victims.

“We’re going to do what we always do. We’re going to wrap our arms around these families, and we’re going to be there with them, not just for the days, but the weeks and the months and the years to come,” he said.

Moment of silence

This comes after another Black Hawk crash in Alabama last month that killed two national guardsmen. There has also been an uptick in near collisions in civilian aviation, prompting the Federal Aviation Administration to issue a "safety alert" to airline staff.

The Kentucky legislature observed a moment of silence for the victims at Fort Campbell Thursday morning.

“The Fort Campbell soldiers that live in our communities, go to our churches ... they go to our schools, their kids do,” Republican state rep. Walker Thomas said. "And this really hurts.”