US President Donald Trump will sign an executive order on Friday that directs the Department of Defense to be known as the Department of War.

The move would restore a name the agency last held in the 1940s and, according to the text of the order seen by the BBC, the aim is to "project strength and resolve".

The department will initially use the new name as a "secondary title" while the administration seeks congressional approval to make the change permanent.

The White House is yet to say how much a rebrand would cost, but US media expect a billion-dollar price tag for the overhaul of hundreds of agencies, emblems, email addresses and uniforms.

The Department of Defense (DoD) - which oversees the US armed services - is the successor to the War Department, which was first established as a cabinet-level agency in 1789 and existed until 1947.

It says: "The name 'Department of War' conveys a stronger message of readiness and resolve compared to 'Department of Defense,' which emphasizes only defensive capabilities."

The order says Secretary of Defense Pete Hegseth will be known as secretary of war. It instructs him to recommend and include legislative and executive actions to move toward a permanent renaming of the department.

The responsibility of creating executive departments rests with the US Congress.

In August, Trump told reporters he was confident Congress would support the idea - if their support was needed.

Democratic Senator Andy Kim of New Jersey said the renaming was a childish idea, adding: "Americans want to prevent wars, not tout them."

The Department of War was established by George Washington but was rebranded following World War II.

Trump has repeatedly floated the idea of the name change, arguing that the US has an "unbelievable history of victory" in both world wars under the previous name.

Trump and Hegseth have sought to refocus the department on "warfighting" and a "warrior ethos".

They have argued that the department has become too focused on diversity, equity and inclusion programmes and "woke ideology".

Earlier on Thursday, Trump downplayed suggestions about seeking the Nobel Peace Prize.

"All I can do is put out wars," he told CBS News, the BBC's US partner. "I don't seek attention. I just want to save lives."

The renaming of the department marks the president's 200th executive order signed since he took office.

Although the renaming was long expected, it comes on the heels of China unveiling a range of new weapons, drones and other military hardware in a massive parade that many interpreted as a clear message to the US and its allies. (BBC)