Three Army helicopter pilots are dead after two Apaches crashed in central Alaska while returning from a training mission, according to military officials.

The Apache helicopters are from the 11th Airborne Division’s 25th Aviation Regiment at Fort Wainwright. They crashed Thursday near Healy, Alaska, about 80 miles southwest of Fairbanks. Three of the four people in the helicopters are dead, said Capt. Molly Treece, an Army spokeswoman. The survivor was taken to a hospital, Treece said.

It was not immediately clear what caused the crash.

“First responders are on the scene. The incident is under investigation and more information about the incident will be released when it becomes available,” the 11th Airborne Division said in a statement.

The crash is at least the second involving the Apache helicopters in Alaska this year. In February, two soldiers were injured when their Apache crashed at Talkeetna Airport, in southern Alaska.

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