Three people died after a UH-60 Black Hawk helicopter crashed Thursday after taking off from an airport in St. Cloud, Minnesota.

The Minnesota National Guard confirmed to NBC News it lost contact with the Black Hawk at around 2 p.m. CST and authorities are searching for it. Master Sergeant Blair Heusdens said the helicopter was conducting a maintenance test flight and that three Guardsmen were on board.

All three Guardsmen on the helicopter were declared dead, Minnesota Gov. Tim Walz confirmed Thursday evening. Walz, a former Guardsman, said that the soldiers were "brothers in arms."

Brig. Gen. Sandy Best said the state's guard was devastated over the loss and is investigating the cause of the crash. She did not identify the deceased, as the family has not yet be notified.

The Black Hawk's last known location was about 10 miles southwest of the airport, according to NBC affiliate KARE. Crews from St. Paul Fire and Rescue and the Minnesota State Patrol located wreckage near Kimball, Minnesota, KARE reports.

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The St. Paul Fire Department said it was supporting the Minnesota Aviation Rescue Team for a report of an aircraft down in St. Cloud following a mayday. St. Cloud is about 76 miles northwest of Minneapolis and St. Paul.