Donald Trump's social media account on Tuesday removed a video showing fake headlines about a "unified reich" if he wins the 2024 US election, as President Joe Biden accused his election rival of using "Hitler's language."

Trump's campaign blamed an inattentive staffer for reposting the 30-second clip, which flashed a series of fictitious news stories painting a picture of American prosperity, with one including the term normally associated with Nazi Germany.

Biden branded the staffer story a "lame" excuse and launched a full-court press over the latest friction point between the two November presidential contenders.

"This is the same guy that uses Hitler's language, not America's," Biden told donors during a fundraiser in Boston.

"It's no surprise" that Trump was reported as saying "that Hitler did some, quote, 'some good things,'" Biden added, referring to a recent CNN story.

As Biden met supporters, he released a short clip of his own on X, the former Twitter, in which he is seen looking at his phone and appearing shocked that the offending video was on Trump's official Truth Social account.

"Wow. A unified reich? That's Hitler's language, that's not America's," Biden says.

The pro-Trump video was posted Monday afternoon and was removed around 19 hours later.

"What happens after Donald Trump wins? What's next for America?" a voiceover asks in the clip as the hypothetical headlines are shown.

Amid headlines including "Economy booms!" and "Border is closed," one mentions the creation of a "unified reich."

No direct reference to Nazis is made in the clip, but the word "reich" is commonly used in reference to the Third Reich of Nazi Germany.

Other references in the video, which appeared to have multiple copy-and-pasted chunks of text to fill out the "newspaper" background, mention World War I. The "unified reich" headline appears to reference the 1871 unification of Germany.

As Biden ramped up the campaign rhetoric, he accused Trump of still being obsessed over his 2020 loss.

"It unhinged him," the president said in Boston. "The guy's a little unhinged."

- 'Rule as a dictator' -

In a statement, Trump campaign spokeswoman Karoline Leavitt said the post had no official backing and that the "reich" reference was unintentional.

"This was not a campaign video, it was created by a random account online and reposted by a staffer who clearly did not see the word," she said.

Trump didn't respond to shouted questions about the video as he attended his historic criminal trial in New York.

The post comes as Trump has repeatedly sought to portray Biden as failing to curb anti-Semitism in the United States during a period of rising tensions fueled by the war in Gaza.

But Trump himself has repeatedly used rhetoric that carries clear echoes of Nazi ideology, including describing domestic opponents as "vermin" and immigrants as "poisoning the blood" of the United States.

While president, Trump in 2017 said some neo-Nazi marchers during violent protests in Charlottesville, Virginia -- who had chanted "Jews will not replace us" -- were "very fine people," and he has dined with white nationalists at his Florida estate.

Trump has a long history of anti-Semitic behavior, the Biden campaign said Monday.

"Donald Trump is not playing games. He is telling America exactly what he intends to do if he regains power: rule as a dictator over a 'unified reich',' spokesperson James Singer said.