Military father Khizr Khan in a Tuesday appearance on CNN. Screenshot/CNN Khizr Khan, the father of a slain Muslim American soldier who has engaged in a back-and-forth with Donald Trump over the past several days, on Tuesday excoriated the Republican nominee for accepting a Purple Heart from a veteran at a campaign rally.

Khan, whose son died protecting his unit in Iraq, said Trump should have given the medal back. He also accused Trump of dodging the Vietnam War draft.

"You should have pinned that back to that veteran's chest and should have hugged him and thanked him," Khan said in an interview with CNN's Anderson Cooper. "If he would have been sensible, he would have known what it takes to earn that Purple Heart."

At the campaign rally in Ashburn, Virginia, Trump said a veteran in the audience had offered him his medal, given to military members who are wounded or killed while serving. He thanked the lieutenant colonel onstage and joked: "I always wanted to get the Purple Heart. This was much easier."

But Khan clearly did not find Trump's comments amusing.

"You had your chance. You escaped. You dodged the draft," Khan said, referring to a recent report in The New York Times that said Trump received five deferments during the Vietnam War. "And now you want an easy Purple Heart in your pocket?"

Donald Trump accepting a Purple Heart from a veteran at a campaign rally in Virginia on Tuesday. Screenshot/RightSide Broadcasting Khan became visibly emotional at times during the interview with Cooper, and at one point he apologized for raising his voice.

Trump criticized Khan on Monday for appearing on television multiple times after speaking at the Democratic National Convention last week. In the convention speech, which catapulted Khan and his wife to national prominence, he slammed the Republican nominee for his comments about veterans and Muslim immigration, and he questioned Trump's knowledge of the US Constitution.

Trump subsequently mused on whether Khan's wife, Ghazala, was permitted to speak during the speech, prompting her to write in an editorial in The Washington Post that "without saying a thing, all the world, all America, felt my pain."

Watch a clip from the interview below: