Khizr Khan: Trump has a 'black soul'

"He talks about excluding people, disrespecting judges, the entire judicial system, immigrants, Muslim immigrants. These are divisive rhetoric that are totally against the basic constitutional principles," he said.

He also said Trump lacks key traits that presidents need.

"Two things are absolutely necessary in any leader or any person who aspires, wishes, to be a leader. That is moral compass and second is empathy," Khan said.

Khan called on House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell to withdraw their support for Trump.

"It is a moral obligation -- history will not forgive them," he said. "This election will pass, but history will be written. The lack of moral courage with remain a burden on their souls."

He said those GOP leaders have a "moral, ethical obligation to not worry about the votes but repudiate him; withdraw the support. If they do not, I will continue to speak."

Khan pushed back on Trump's suggestion that his wife, who was also on stage at the DNC, was not allowed to speak. He said she has high blood pressure and didn't want to speak for fear she wouldn't be able to hold herself together discussing her Gold Star son on stage.

"For this candidate for presidency to not be aware of the respect of a Gold Star mother standing there, and he had to take that shot at her, this is height of ignorance," Khan said. "This is why I showed him (the) Constitution. Had he read that, he would know the status a Gold Star mother holds in this nation."

Trump had first suggested Khan's wife was not allowed to speak in an interview with The New York Times' Maureen Dowd, saying: "I'd like to hear his wife say something."

Then, he told Stephanopoulos, "If you look at his wife, she was standing there, she had nothing to say, she probably -- maybe she wasn't allowed to have anything to say, you tell me."

Khizr Khan's wife, Ghazala Khan, responded to Trump in a Washington Post op-ed Sunday.

"Walking onto the convention stage, with a huge picture of my son behind me, I could hardly control myself. What mother could? Donald Trump has children whom he loves. Does he really need to wonder why I did not speak?" she wrote.

"Donald Trump said that maybe I wasn't allowed to say anything. That is not true," Ghazala Khan wrote. "My husband asked me if I wanted to speak, but I told him I could not. My religion teaches me that all human beings are equal in God's eyes. Husband and wife are part of each other; you should love and respect each other so you can take care of the family."

Khizr Khan had also said in an interview with The Washington Post that Trump's attack on his wife was "typical of a person without a soul."

"Emotionally and physically -- she just couldn't even stand there, and when we left, as soon as we got off camera, she just broke down," Khan told the Post. "And the people inside, the staff, were holding her, consoling her. She was just totally emotionally spent. Only those parents that have lost their son or daughter could imagine the pain that such a memory causes."

Trump, in a statement released Saturday by his campaign, called Capt. Khan "a hero to our country and we should honor all who have made the ultimate sacrifice to keep our country safe."

But after Khan's Sunday CNN interview, Trump tweeted: "I was viciously attacked by Mr. Khan at the Democratic Convention. Am I not allowed to respond? Hillary voted for the Iraq war, not me!"

Earlier Sunday, he also tweeted: "Captain Khan, killed 12 years ago, was a hero, but this is about RADICAL ISLAMIC TERROR and the weakness of our "leaders" to eradicate it!"

Trump also pushed back on Khan's on-stage suggestion that he has "sacrificed nothing and no one" in an interview with with ABC News' George Stephanopoulos aired Sunday on "This Week."

"I think I've made a lot of sacrifices. I work very, very hard," Trump said. "I've created thousands and thousands of jobs, tens of thousands of jobs, built great structures. I've had tremendous success. I think I've done a lot."