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Eric Trump went "On The Record" tonight to discuss the controversy surrounding his father not aggressively disavowing the Ku Klux Klan during a recent interview.

The Republican presidential front-runner had been asked about support for his campaign from the KKK and David Duke by CNN's Jake Tapper on Sunday, with Trump repeatedly saying he "didn't know" about Duke or the white supremacist group enough to disavow them.

Trump's son told Greta Van Susteren tonight that the whole thing is "ridiculous," since his father has denounced Duke and the KKK countless times.

"My father's a great man. Those three letters shouldn't even be used in the same sentence with my father," Trump said. "This is really politics at its ugliest."

He said that his family was prepared for the vicious mudslinging that would come along with a presidential campaign, but this and other attacks - like Ted Cruz's assertion that Trump has mob ties - are truly awful.

"These guys are drowning and they're trying to grab at anything they can, and they're trying to pull him under with them," Trump said. "But I think people are seeing it."

Watch more above.

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