Fox Business host Stuart Varney asked the real estate mogul if he would follow the U.K.'s example of revoking passports from people who've traveled overseas to fight for ISIS, in addition to closing some mosques.
"I would do that," Trump said. "Absolutely. I think it's great. I know they have a lot of proposals over there. If you go out, you go fight for ISIS, you can't come back. Why can't you do it? You can do it here."
"Can you do it?" Varney pressed. "Can you close a mosque? I mean, we do have religious freedom."
"Well, I don't know," Trump backpedaled. "I haven't heard about the closing of the mosque. It depends on if the mosque is, you know, loaded for bear, I don't know. You're going to have to certainly look at it."
The real estate mogul reiterated that under a Trump presidency, no one who left the U.S. to fight for the terror group would be allowed back in.