Presidential candidate Donald Trump joked about Nazi ovens to Jewish executives, an ex-employee has told American media.

The woman who headed up the Trump Tower project, Barbara Res, claimed to MSNBC that the former president once joked that he had hired a German manager, and Jews should “watch out” because “he remembers the ovens”.

A lead engineer in charge of construction in Trump’s company in the 1980s and 1990s, Res has authored a memoir, Tower of Lies, about the nearly two decades she spent working for the former president.

She told MSNBC on Sunday that she was reminded of the time that her boss hired “a residential manager, a German guy.”

Trump “was bragging to us executives, there were four of us, about how great the guy was and he was a real gentleman, and he was so neat and clean. And he looked at a couple of our executives who happen to be Jewish, and he said, ‘Watch out for this guy, he sort of remembers the ovens,’ you know, and then smiled.

“Everybody was shocked,” Res said. “I couldn’t believe he said that. But he was making a joke about the Nazi ovens and killing people, and that’s the way he was.”

Res had been reminded of Trump’s past comments when the former president praised notorious fictional cannibal, Hannibal Lecter, during a rally in New Jersey last month.

“The late, great Hannibal Lecter is a wonderful man,” Trump said,

The new accusations about Trump’s remarks come as both parties vie for the Jewish vote ahead of November’s presidential election, which is expected to be a rematch between Trump and President Joe Biden.

Back in March, Trump said, "Any Jewish person that votes for Democrats hates their religion, they hate everything about Israel and they should be ashamed of themselves."

“The Democrat Party hates Israel," he went on during an interview with his former adviser Sebastian Gorka.

Meanwhile, the Biden campaign has hosted regular “Jewish Women for Joe” Zoom calls and is set to hire a faith engagement director with Jewish voters as a major part of their portfolio.

CNN has reported that several Jewish leaders have complained that they have not seen enough direct engagement from Biden's campaign, however.