All eight people on board a charter flight have died after the aircraft crashed at a remote military radar installation in western Alaska on Thursday, the US military has confirmed.

The aircraft, a Cessna 441 operated by Anchorage-based firm Security Aviation, went down near Cape Newenham Long Range Radar Site Airport at around 12.15 pm local time. The airfield is located approximately 450 miles west of Anchorage.

Clint Johnson, the National Transportation Safety Board’s Alaska region chief, said the flight had departed from Anchorage International Airport carrying two pilots and six passengers. It is understood to have crashed while approaching Cape Newenham.

The U.S. Army Corps of Engineers said in a statement that the plane had been chartered by the USACE and that two civilian employees of the branch were on board at the time of the crash. The press release says officials are cooperating with the investigation and that next of kin have been notified.

In a statement, U.S. Air Force Lt. Gen. Robert Davis, commander of Alaskan Command, the Alaskan North American Aerospace Defense Command Region and Eleventh Air Force, paid tribute to those killed.

“This is a devastating loss for our military family and the communities we serve,” Davis said.

Meanwhile, Alaska Senator Lisa Murkowski said that she had traveled “extensively” with Security Aviation in the past.

“Alaska is praying for those on board, their loved ones, and the team at Security Aviation,” the senator added.

Congressman Nick Begich also issued a statement saying he and his wife “join Alaskans across our state in praying for everyone affected and the entire Security Aviation family.”

He described those on board as “dedicated professionals carrying out a vital mission in a demanding environment. Our absolute priority right now is providing unwavering support to their families, friends and teammates during this devastating time. We are profoundly grateful for the swift and tireless response of our search and recovery professionals.”

The Pacific Air Forces Regional Support Center maintains the Cape Newenham installation. It is part of a chain of isolated radar outposts designed to monitor aircraft movements within Alaskan airspace and along its borders.

Military authorities described the plane as a “civilian-contracted aircraft,” though they did not disclose further details about the passengers’ work.