The presidential candidate is sitting down for an interview with Barbara Walters

Donald Trump Says Syrian Refugees Should Be Kept Out of U.S.: 'We Have No Idea Who These People Are'

Donald Trump will undoubtedly have plenty say when he sits down with Barbara Walters for an interview airing Friday on 20/20.

In the first clip from the interview, Trump sounds off an idea presented by Sen. Ted Cruz, one of his rivals for the Republican presidential nomination. Cruz has argued that only Christian refugees should be allowed into the U.S., but argues no refugees should be allowed in.

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The problem is we don’t know if they are Christian are not. I would certainly say that would be superior,” Trump tells Walters. “But we don’t know if they are Christian are not. We have no idea who these people are. They have no papers, they have no paper work. You can get forged documents very easily in Syria.”

Before being interviewed by Walters on Monday, Trump told attendees at a Knoxville, Tennessee rally that Syrian refugees who have settled in the U.S. should be deported back home to a “safe zone” in their country.

On Tuesday, Trump told PEOPLE that the Knoxville rally exemplified how campaigning could be good for his health (he’s lost 15 lbs. since hitting the trail).

“One of the reasons is I have big crowds and they’re very exciting stops,” Trump told PEOPLE. “And when you speak and you really are going at it, you tend to I never thought about it, but speaking is almost a form of exercise. It’s very exhilarating. Last night I was in Knoxville, Tennessee, speaking to 12,000 great people. You get so worked up, you don’t feel like eating after that.”