The three were assigned to a general support aviation battalion in St. Cloud, Minnesota, the national guard said in a statement, and their unit had returned in May from a nine-month medical evacuation deployment to the Middle East.
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The soldiers were the only people aboard the UH-60 Black Hawk when it crashed Thursday. its last known location was about 10 miles southwest of a St. Cloud airport at about 1:55 p.m., according to guard officials and NBC News affiliate KARE.
"Shortly after takeoff, the pilots initiated a mayday call," said Major Gen. Jon A. Jensen of the Minnesota National Guard in a news conference Saturday.
The crew was on a routine maintenance flight, the type of which was "conducted almost daily," when the Black Hawk went down, he said.
Jensen said the Minnesota National Guard's UH-60s were grounded as Army investigators, with the assistance of the state guard, tried to determine what caused the crash.
"We expect our UH-60s will begin flying again shortly," he said.
He also addressed the families of the fallen: "You are not alone in your grief."
Dennis Romero writes for NBC News and is based in Los Angeles.
Cristian Santana, Nadine Comerford and Mosheh Gains contributed.