The Army has grounded aviation units for training following deadly helicopter crashes in Alaska and Kentucky.
The military branch said Friday that the suspension of air operations was effective immediately.
Army spokesperson Lt. Col. Terence Kelley said units were grounded until they complete training, according to The Associated Press. The training for active-duty units is slated to take place between May 1-5, and Army National Guard and Reserve units will have until May 31.
"The move grounds all Army aviators, except those participating in critical missions, until they complete the required training," the Army said in a statement.
The crashes killed 12 in the past month and two Army helicopters collided near Healy, Alaska, on Thursday – killing three and injuring a fourth. Their names were not immediately released.
Military investigators were expected to arrive at the crash site by Saturday.
This comes after nine soldiers were killed in March when two U.S. Army Black Hawk medical evacuation helicopters crashed during routine evening craning northeast of Fort Campbell, Kentucky.
That crash also remains under investigation, but The Associated Press said the Army noted there is "no indication of any pattern between the two mishaps."
In February, two soldiers were hurt when an Apache helicopter rolled after taking off from Talkeetna. It was traveling to Joint Base Elmendorf-Richardson in Anchorage from Fort Wainwright.
The Associated Press contributed to this report.