On Thursday night, two U.S. Army helicopters crashed while returning from a training exercise in Alaska. The incident resulted in the deaths of three individuals, with the cause remaining unknown, as reported by the Washington Post.

Each helicopter had two occupants, and they were AH-64 Apache choppers traveling from Fort Wainwright near Fairbanks before the collision occurred near Healy.

An investigation is currently underway, and officials have indicated that more information will be made available as it becomes known.

This marks the second time this year that military helicopters in Alaska have been involved in a crash, following an Apache helicopter spinning out during takeoff in Talkeetna in February, injuring two soldiers. The following month, nine soldiers lost their lives when two Army Black Hawk helicopters collided during a routine nighttime exercise near Fort Campbell, Ky.

Healy, where the latest crash happened, is a small town with a population of about 1,000 people located in Alaska’s interior.

It is approximately 250 miles north of Anchorage and is a favored destination for visitors who come to see Denali, the highest peak on the continent.