NEW YORK, United States (AFP) — Another day campaigning for president, another controversy for US tycoon Donald Trump, who was lampooned yesterday over a tweet that appeared to show Nazis marching under the White House.

“Make America Great Again,” was the catchphrase alongside a montage of the US flag merged with his face, banknotes, the White House, and marching armed soldiers.

Just one problem, the soldiers weren’t American heroes, but men dressed up as Nazis from the Waffen SS.

Critics mocked Trump for failing to spot the difference between heros and Nazis, who were responsible for the murder of six million Jews. His campaign swiftly deleted the tweet.

A spokesperson blamed the foul-up on an intern.

“A young intern created and posted the image and did not see the very faded figures within the flag of the stock photo,” she told AFP in a statement.

“The intern apologised and immediately deleted the tweet.”

John Schindler, a former national security affairs professor at the US Naval War College, was one who spotted the mistake.

“These guys are dressed as late (1944-45) WW2 Waffen-SS infantry. Nothing to debate here. Way to go, Trump!” he tweeted.

Schindler told AFP the camouflage tunic and eagle insignia on the left arm were worn only by the Waffen SS.

“If you know your German uniforms it’s very obvious,” he said. But he was still charitable towards the Trump team.

Up to a point.

“This could happen to anybody — when you have social media interns who don’t know anything about history and who are clearly not doing any research,” he said.

Trump has blazed onto the campaign trail, offending his rivals and the Latino community by branding Mexicans as rapists.

Yet yesterday he topped the crowded field of Republican presidential candidates for a second straight week, according to a new Suffolk University/USA TODAY poll.

He was in the lead with 17 per cent of support among party faithful and independents, ahead of Jeb Bush, the son of one former president and the brother of another.