The firing squad execution of Nidal Hasan, the army psychiatrist who killed 13 people at Fort Hood, Texas, in 2009 will be broadcast live.
US Defence Secretary Pete Hegseth told Human Events Daily with Jack Posobiec on Thursday that Hasan's execution would be carried out on December 3 at Fort Hood.
"We'll make sure that people are able to watch it, that it's public," Mr Hegseth said. "Because people need to understand that there's serious consequences for these types of things."
The last public execution in the US was in 1936.
"The Secretary is correct. It will be livestreamed. Details will follow," a Pentagon official told Reuters.
President Donald Trump this week ordered the use of a firing squad to execute Hasan.
Hasan, a former US Army major, later described his shooting spree as retaliation for US wars in the Muslim world.
Putting Hasan to death by Army firing squad was approved by Mr Trump at the recommendation of Mr Hegseth, Pentagon spokesman Sean Parnell said on X.
Mr Parnell said Hasan shouted "Allahu Akbar" during the attack, in which 12 unarmed active-duty soldiers and a retired serviceman were killed, and 32 others wounded.
Death by firing squad was one of several forms of capital punishment the Trump administration recently added to permissible forms of execution for the gravest of federal crimes, along with electrocution and gas asphyxiation.
The number of federal execution options was expanded in part because of increasing difficulties in obtaining drugs for lethal injections, which have also proved challenging to carry out for other reasons at times.
Plans by the state of Tennessee to execute a woman for the first time in more than 200 years went awry last week when prison personnel botched an attempt to administer a lethal injection, leaving the death-row inmate, Christa Pike, alive but unconscious and in hospital on life support. She regained consciousness on Tuesday.
Pike's lawyers had previously urged that the Tennessee Department of Correction to consider an alternative to lethal injection, such as hanging or firing squad, in anticipation of the trouble executioners faced in establishing a sound intravenous line.
A military jury sentenced Hasan to death in August 2013, after finding him guilty of 45 counts of premeditated murder and attempted premeditated murder for opening fire with a laser-sighted handgun in a medical centre at the sprawling central Texas military base.
The shooting came weeks before Hasan, now 56, was scheduled to be sent to Afghanistan. He was left partially paralysed and confined to a wheelchair from being shot by police upon his arrest.
In a statement responding to Mr Trump's decision, the group Death Penalty Action, which opposes capital punishment, said: "There is nothing Donald Trump loves more than the power to kill."
Military executions are rare, and under the Uniform Code of Military Justice a death sentence imposed by court-martial may not be carried out "until approved by the president".
If Hasan is put to death, it would mark the first military execution since 1961, the group said. According to the Death Penalty Information Centre, the 1961 execution was carried out by hanging. The apparent last known execution by a US military firing squad was one carried out "by musketry" in November 1945, the centre reported.
At least five states have firing squads on the books, according to the Death Penalty Information Centre. In 2025, South Carolina carried out the first such execution in the United States in 15 years.
