David Duke, a white nationalist and a former KKK grand wizard, urged his radio show listeners to vote for Trump, saying that a ballot cast against the New Yorker would be "treason to your heritage."
He also called Trump's candidacy an "insurgency that is waking up millions of Americans" and prompted his fellow nationalists to volunteer for the campaign.
When he was given the opportunity to denounce Ku Klux Klan leader David Duke on a political talk show on Sunday, Republican presidential front-runner Donald Trump declined to take it.
During the CNN interview, "State of the Union" host Jake Tapper asked the billionaire:
"Will you unequivocally condemn David Duke and say that you don't want his vote or that of other white supremacists in this election?"
Trump told CNN:
"I don't know anything about David Duke, okay? I don't know anything about what you're even talking about with white supremacy or white supremacists."
Shortly after Duke announced his support, the Anti-Defamation League urged Trump to "distance" himself from the prominent Klan figure.
But on Sunday, when pressed again if he would condemn Duke, Trump responded that he'd "have to look at the group."
"You wouldn't want me to condemn a group that I know nothing about. I would have to look. If you would send me a list of the groups, I will do research on them," he said. "And, certainly, I would disavow if I thought there was something wrong."
Tapper questioned: "The Ku Klux Klan?"
"But you may have groups in there that are totally fine," the GOP candidate shot back. "And it would be very unfair. So, give me a list of the groups, and I will let you know."
Trump's final words on the subject:
"Honestly, I don't know David Duke. I don't believe I have ever met him. I'm pretty sure I didn't meet him. And
I just don't know anything about him."
Donald Trump declines to condemn KKK leader David Duke
Trump declines to condemn Ku Klux Klan
Hillary Clinton, in response to a question about Trump's remarks, said, "It's pathetic."