(NewsNation) — The Army National Guard ordered all helicopter units to be grounded for a review of safety “policies and procedures” after two crashes that happened within weeks of each other. 

An Army National Guard news release said the stand-down went into effect Monday, though officials did not announce it publicly until Tuesday.

“We are a combat force with helicopters training or on mission worldwide every day,” Lt. Gen. Jon A. Jensen, director of the Army National Guard, said in a statement. “Safety is always at the top of our minds. We will stand down to ensure all of our crews are prepared as well as possible for whatever they’re asked to do.”

This grounding follows a Feb. 12 crash in Utah and another from Friday in Mississippi. 

No deaths were reported in Utah.

Mississippi Army National Guard pilots Bryan Andrew Zemek and Derek Joshua Abbott perished in the second crash when their aircraft went down in a wooded area near Baldwyn.

Both crashes involved AH-64D Apache helicopters. Information on what caused the crashes has not been publicly released, but NewsNation partner The Hill reports the Army’s Combat Readiness Center is investigating them.

“I wanted to extend my deepest condolences to the families and to the friends of our fallen soldiers,” Mississippi Gov. Tate Reeves said at a press briefing Saturday. “We will always remember these dedicated soldiers for their honorable service, and we grieve with the families during this tragic time.”

Abbott and Zemek had served at an Army aviation support facility in Tupelo, Mississippi. 

A native of Oxford, Zemek is survived by his wife and four children, while Abbott had three children and had been married for 18 years. 

When asked at a press briefing Tuesday if he had any concerns about the Army’s aviation program, Maj. Gen. Pat Ryder, the Pentagon press secretary, answered that senior leadership in all military branches is “making safety a priority.”

“Broadly speaking, safety is something that we’re always going to be concerned about and take seriously,” Ryder said, adding that this was evidenced “by the fact that the National Guard Bureau recognizes, ‘Hey, we need to take a moment here to stand down, review safety procedures and processes and make sure we can look each other in the eye and go out there and do our mission safely.'”

NewsNation has reached out to the National Guard to clarify how long the stand-down could last.

NewsNation digital producer Sean Noone contributed to this report.