Army leadership ordered an aircraft withdrawal Friday after two fatal helicopter crashes, the most recent of which killed three soldiers and injured a fourth in Alaska on Thursday.

Army Chief of Staff James McConville’s order grounded all Army airmen, except those on critical missions, until they come in, the Army said in a statement.

“The safety of our Airmen is our top priority, and this recall is an important step in making sure we are doing everything we can to prevent accidents and protect our personnel,” McConville said in a statement.

Twelve soldiers have died in helicopter crashes since March.

On Thursday, three soldiers were killed and a fourth injured after two Apache helicopters collided mid-air in Alaska and crashed, the 11th Airborne Division said. They were returning to Fort Wainwright in Fairbanks at the time.

On March 29, nine soldiers died when the two Black Hawk helicopters they were traveling in crashed in Kentucky, west of Fort Campbell.

Both incidents involved training exercises.

“During this recall, we will focus on safety and training protocols to ensure our pilots and crews have the knowledge, training, and awareness to safely complete their assigned mission,” McConville said in the statement.

The Army said it will review the «approval/risk management process,» aircraft maintenance training, how flight briefings are conducted, and flight planning, with the goal of reducing risks, among other issues.

The cause of Thursday’s crash in Alaska is under investigation, and the identities of the soldiers who died have not yet been released.

They were from the 1st Attack Battalion, 25th Aviation Regiment based at Fort Wainwright.

The accident occurred near Healy, a community about 80 miles southwest of the military base in Fairbanks, the military said.