The candidacy of Donald Trump to become President of the United States has become overshadowed by a row over a speech given by the father of a dead U.S. Muslim soldier.

At the Democratic convention Khizr Khan paid tribute to his son Humayun’s valor. He was killed in the line of duty in Iraq in 2004. 

CCTV America’s Elaine Reyes sat down with Khizr Khan and talked to him about his son, the speech’s impact and some of the world events that are taking center stage in the U.S. presidential campaign.

Watch the full interview here.

Mr. Khan also criticized Trump’s proposed ban on Muslim immigration and accused the candidate of sacrificing “nothing.”

Trump’s responses have drawn criticism from across the political spectrum and his poll numbers are slipping. Trump responded on social media saying: “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!”

Trump went onto say Mr. Khan’s son was a hero but stood by his proposals to ban Muslim immigration in a bid to stop potential terrorists entering the U.S.

But he then seemed to equate his own sacrifices in the business world with the Khan’s sacrifice of their son. Now, there are also questions surrounding Trump’s explanations of how he avoided military service in the Vietnam war.

And in a dramatic statement the current U.S. President Barack Obama said Tuesday that Trump is unfit for office and Republicans should think about abandoning their candidate.

“There has to come a point at which you say somebody who makes those kinds of statements doesn’t have the judgment, the temperament, the understanding to occupy the most powerful position in the world,” Obama said.