Emergency responders near a site where two military helicopters crashed Wednesday night during a routine training mission in Trigg County, southwestern Kentucky, on Thursday. Brandon Smith/WSMV-TV via Associated Press

FORT CAMPBELL, Ky. — U.S. Army investigators are trying to determine what caused two Black Hawk medical evacuation helicopters to crash during a routine nightime training exercise in Kentucky, killing all nine soldiers aboard. No one was hurt on the ground.

Nondice Thurman, a spokesperson for Fort Campbell, said the deaths happened Wednesday night in southwestern Kentucky during a routine training mission.

A statement from Fort Campbell said the two HH-60 Black Hawk helicopters, part of the 101st Airborne Division, crashed around 10 p.m. Wednesday in Trigg County in southwest Kentucky. The 101st Airborne confirmed the crash about 30 miles (48 kilometers) northwest of Fort Campbell.

One helicopter had five people aboard and the other had four, Brig. Gen. John Lubas, the 101st Airborne deputy commander, said Thursday. The helicopters crashed in a field near a residential area with no injuries on the ground, Lubas said.

An Army spokesperson declined to comment on whether the helicopters collided in the air.

“At this time, there is no determination on the specifics regarding the accident,” Daniel Matthews, a public affairs officer for the 101st Airborne Division, said in an emailed statement Thursday afternoon. Matthews said an aviation safety team from Fort Rucker, Alabama, will investigate the accident.

Lubas said it is unclear what caused the crash.

“This was a training progression, and specifically they were flying a multi-ship formation, two ships, under night vision goggles at night,” Lubas said. He said officials believe the accident occurred when “they were doing flying, not deliberate medical evacuation drills.”

The helicopters have something similar to the black boxes on passenger planes, which records the performance of aircrafts in flight and are used by investigators to analyze crashes.

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

Speaking a news conference Thursday morning, Kentucky Gov. Andy Beshear said the state would do everything it can to support the families of those killed.

“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,” Beshear said.

The Black Hawk helicopter is a critical workhorse for the U.S. Army and is used in security, transport, medical evacuations, search and rescue and other missions. The helicopters are known to many people from the 2001 movie “Black Hawk Down,” which is about a violent battle in Somalia eight years earlier.

Black Hawks were a frequent sight in the skies over Iraq and Afghanistan during the wars conducting combat missions and are also used by the Army’s 160th Special Operations Aviation Regiment. They were also often used to ferry visiting senior leaders to headquarters locations in the Iraq and Afghanistan war zones.

Fort Campbell is located near the Tennessee border, about 60 miles (97 kilometers) northwest of Nashville, and the crash occurred in the Trigg County, Kentucky, community of Cadiz.

Nick Tomaszewski, who lives about a mile from where the crash occurred, said he saw two helicopters flying over his house moments before the crash.

“For whatever reason last night my wife and I were sitting there looking out on the back deck and I said ‘Wow, those two helicopters look low and they look kind of close to one another tonight,’” he said.

The helicopters flew over and looped back around and moments later “we saw what looked like a firework went off in the sky.”

“All of the lights in their helicopter went out. It was like they just poofed … and then we saw a huge glow like a fireball,” Tomaszewski said.

Flyovers for training exercises happen almost daily and the helicopters typically fly low but not so close together, he said.

“There were two back to back. We typically see one and then see another one a few minutes later, and we just saw two of them flying together last night,” he said.

U.S. Defense Secretary Lloyd Austin offered his condolences to the families of those killed.

“My heart goes out to the families of these servicemembers and to the members of the 101st Airborne Division who bravely and proudly serve our country each and every day,” Lloyd said in a statement.

In the Kentucky House and in the Senate, members stood for a moment of silence Thursday morning in honor of the crash victims. Kentucky state Rep. Walker Thomas said the crash occurred about 15 to 20 minutes from his home.

“They’re there to protect us,” Thomas said. “And we’re constantly seeing these helicopters flying over our communities.”

Thomas spoke about how connected Fort Campbell soldiers and their families are to the communities near the Army post.

“The Fort Campbell soldiers that live in our communities, go to our churches … they go to our schools, their kids do,” he added. “And this really hurts.”

By Thursday morning, word of the crash was spreading through the community of Clarksville, Tennessee, just outside Fort Campbell.

Chaterra Watts, a former Army soldier who was stationed at Fort Campbell from about 2015 to 2019, said once she heard about the crash, she jumped on social media to try to find out more and if she knew any of the victims.

“I pray for their friends and their families and just hope that we can all come together as a community and that something positive will come out of something so tragic,” Watts said.

Last month, two Tennessee National Guard pilots were killed when their Black Hawk helicopter crashed along an Alabama highway during a training exercise.

Lovan and Reynolds reported from Louisville, Kentucky. Associated Press writers Bruce Schreiner in Frankfort, Kentucky; Lolita Baldor in Washington and Denise Lavoie in Richmond, Virginia; contributed to this report. AP researcher Rhonda Shafner in New York also contributed.