DONALD Trump said on Tuesday he has never read Adolf Hitler's manifesto 'Mein Kampf' and is not quoting the German dictator when he says illegal immigrants inside the U.S. are poisoning and destroying the blood of America.

In a rally in Iowa, Trump - the clear frontrunner for the Republican presidential nomination - repeated language he has used in recent campaign events about illegal immigrants that has been criticized for being xenophobic and similar to language used by Hitler.

"It's true. They are destroying the blood of our country," Trump told a crowd of supporters in Waterloo, Iowa. "They don't like it when I said that. I never read Mein Kampf." Trump said Hitler used language "in a much different way".

In 'Mein Kampf' (My Struggle), Hitler wrote in 1925: "All great cultures of the past perished only because the original creative race died out from blood poisoning."

Hitler was the dictator of Germany between 1933 until his suicide in 1945. He initiated World War II, and instigated the mass murder of many minorities, including the genocide of six million Jews known as the Holocaust.

In a 1990 article in Vanity Fair, Ivana Trump, Donald Trump's first wife, reportedly told her attorney that Trump kept a book of Hitler's speeches in a bedside cabinet. That article has resurfaced in recent days.

Trump has promised to crack down on illegal immigration and restrict legal immigration if elected to a second four-year term in office.

Trump was in Iowa ahead of the first Republican nominating contest, which takes place in the state on Jan. 15.

Railing against illegal immigrants, Trump said: "They're coming from all over the world. They could be healthy, they could be very unhealthy. They could bring in disease that's going to catch on in our country."

In addition to using the "poison" rhetoric in some recent rallies, Trump also used the "poisoning the blood" language during an interview with The National Pulse, a right-leaning website, that was published in September.

It prompted a rebuke from the Anti-Defamation League, whose leader, Jonathan Greenblatt, called the language "racist, xenophobic and despicable."

Trump, in office between 2017 and 2021, faces a likely rematch with Democratic President Joe Biden in the Nov. 2024 election.

Biden defeated Trump in the 2020 presidential election.

Before Trump's Iowa speech on Tuesday, the Biden campaign blasted out an email citing examples of language used by Trump that echoed Hitler and the Italian dictator Benito Mussolini.

"Donald Trump is parroting autocrats like Hitler and Mussolini, claiming that immigrants are 'poisoning the blood of our country' and calling his political enemies 'vermin', the Biden campaign email said.