Sioux City, Iowa (CNN) Democratic presidential hopeful Beto O'Rourke on Thursday night defended remarks he made in Iowa comparing President Donald Trump's rhetoric on immigration to words and images employed by Nazi Germany.

"I compared the rhetoric that the President has employed to rhetoric that you might've heard during the Third Reich," O'Rourke told a reporter, following a meet and greet at Morningside College in Sioux City. "Calling human beings an 'infestation' is something that we might have expected to hear in Nazi Germany."

He later added, "If we don't call out racism, certainly at the highest levels of power, in this position of trust that the President enjoys, then we're going to continue to get its consequences."

Trump has previously referred to the influx of undocumented immigrants at the southern border as an "infestation." The Nazis regularly invoked the imagery of insects and vermin to denigrate Jews and other enemies. CNN has reached out to the White House for comment.

At an earlier stop in Carroll, O'Rourke raised eyebrows when he invoked Nazi Germany in his remarks, telling caucus-goers, "When the President of the United States has called Mexican immigrants rapists and criminals, he then went on to call asylum seekers animals and an infestation. Now we would not be surprised if in the Third Reich, other human beings were described as an infestation, as a cockroach, or as a pest that you would want to kill. But to do that in 2017 or '18 in the United States of America, it doesn't make sense."

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