The Army announced Tuesday night that it will award Spc. Aleksander Skarlatos of the Oregon National Guard the Soldier's Medal for his actions to stop a gunman last week on a Paris train.

The Soldier's Medal is the highest award for bravery outside of combat, the Army statement said.

"On behalf of our Army, I commend Specialist Aleksander Skarlatos for his heroic actions Friday that saved hundreds of lives by awarding him the Soldier's Medal," said Gen. Mark Milley, chief of staff of the Army. "His extraordinarily heroic effort, at the risk to his own life, truly exemplifies our Army values. I am proud to call you a hero and a soldier."

After hearing gunshots on the Paris-bound train, Skarlatos and two other Americans charged the heavily armed gunman and used the gunman's own weapon to knock him unconscious. The gunman was carrying an AK-47, a pistol, a box cutter and hundreds of rounds of ammunition.

Airman 1st Class Spencer Stone also assisted in subduing the gunman. The Air Force announced Monday that he would receive the Airman's Medal, that service's highest non-combat bravery award.

Stone, Skarlatos and their civilian childhood friend Anthony Sadler received the French Legion of Honor, France's highest recognition, in a ceremony on Monday.

The French government formally launched a terrorism investigation into the incident on Tuesday, the Associated Press reported, after discovering that Ayoub El Khazzani had watched a radical Islamic video on his phone minutes before the attack.

Gen. Mark Welsh, chief of staff of the Air Force, said Stone, who was injured in the incident, could be eligible for the Purple Heart if the investigation finds it was a terrorist attack, citing past precedent of the 2009 shooting at Fort Hood, Texas.