Republican Trump was due to make the announcement from the Oval Office at 2:00 pm (1800 GMT), according to his daily schedule, which did not give further details about the event.

"The President will be making an exciting announcement related to the Department of Defense," White House Press Secretary Karoline Leavitt said in a statement sent to AFP.

Leavitt also gave no other details about what Trump would say.

The event will be Trump's first in public for a week.

Trump dubs himself a "peace president" and claims he deserves the Nobel Peace Prize for ending at least six wars since returning to office -- though Ukraine and Gaza ceasefires remain out of reach.

Despite that, he has said several times in recent weeks that he wanted to change the name to the Department of War, saying its current terminology was too "defensive."

"That was the name when we won World War I, we won World War II, we won everything," Trump told reporters on August 25.

"'Defense' is too defensive. We want to be defensive, but we want to be offensive too. We have to be. It just sounded to me better," he added.

Trump said he didn't know if Congress had to approve a name change, but said he was sure lawmakers would go along with it if so.

Secretary of Defense Pete Hegseth also hinted at the coming change during a marathon cabinet meeting last week.

"It's not just about words -- it's about the warrior ethos," the military veteran and former Fox News contributor said, while adding: "We don't want war, we don't seek it. You are the peace president, sir."