Defense Secretary Pete Hegseth said the execution of Nidal Hasan by firing squad would be broadcast publicly, arguing the American people needed to see the consequences of serious crimes.
"We'll make sure that people are able to watch it, that it's public, because people need to understand there's serious consequences for these types of things," Hegseth said.
Hasan opened fire at a medical processing center at Fort Hood on 5 November 2009, killing 13 people and wounding dozens more. A military jury sentenced him to death in 2013, and he has been held at Fort Leavenworth in Kansas since. The last known case of a military firing squad in the US was in November 1945.
The announcement comes as the Pentagon faces criticism over the US war on Iran. Democratic Senator Chris Murphy accused Hegseth of being "determined to hide the cost and the consequences of this war from the American public". Murphy claimed the Pentagon blocked him from visiting a military base in Qatar and that an Iranian strike on the US embassy in Riyadh was worse than the public had been led to believe.
Separately, President Donald Trump has promised not to attack Iran before November's US midterm elections, outlining a pause on a war he has struggled to end after almost eight months. A Reuters/Ipsos survey from late September found that only about a third of Americans approved of the strikes on Iran.