Two U.S. Army helicopters crashed Thursday in Alaska returning from a training flight, the second accident involving military helicopters in the state this year. Each helicopter carried two people, said John Pennell, a spokesperson for the U.S. Army Alaska. Pennell said he did not immediately have any other information he could share about the condition of those involved. First responders were on the scene at the crash site near Healy, Alaska, a statement from the U.S. Army Alaska said.

The AH-64 Apache helicopters were from Fort Wainwright, based near Fairbanks. Officials said the incident was under investigation and more details would be released when they become available.

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Austin McDaniel, a spokesperson for the Alaska State Troopers, said the state agency was not involved in the response. In February, two soldiers were injured when an Apache helicopter rolled after taking off from Talkeetna.

The aircraft was one of four travelling to Joint Base Elmendorf-Richardson in Anchorage from Fort Wainwright. Healy is located about 10 miles (16.09 kilometers) north of Denali National Park and Preserve or about 250 miles (402 kilometers) north of Anchorage.

Healy is a community of about 1,000 people located on the Parks Highway in Alaska’s interior region. It is a popular place for people to spend the night while visiting the nearby park, which is home to Denali, the continent’s tallest mountain.

Healy is also famous for being the town closest to the former bus that had been abandoned in the backcountry and was popularised by the book “Into the Wild” and the movie of the same name.