Transcript for Donald Trump Fires Back Against GOP Rivals on 'The Late Show'
Okay, race for president. "Your voice, your vote" and Donald Trump back on late night TV last night talking to Stephen Colbert. Also firing back against his rivals. While Ben Carson is backtracking on those comments, his controversial comments he made about muslims. Tom llamas tracking it all. Good morning, Tom. Reporter: Good morning to you. Some candidates were growing in popularity earlier had stayed out of Donald Trump's way now sharpening their attacks. As the front-runner just gets stronger and Dr. Ben Carson still drawing huge crowds and tells me what it would take for him to vote for a Muslim to be president. Donald Trump. Reporter: Overnight Donald Trump taking his campaign to late night. You are setting the world on fire right now. Well, we're having a lot of fun and I think we're hitting some pretty good issues. Reporter: As trump was yucking it up. Anybody you'd like to apologize to yourself right now? No. No? Reporter: His rivals going after him hard. It might seem that Donald Trump's getting a little nervous, all of us will be revealed over time and under pressure. Up to now he hasn't answered serious questions about national security and until he does there should be concerns. Reporter: Trump then slamming Rubio over immigration tweeting senator Marco amnesty Rubio who has worst voting record in senate just hit me on national security but I said don't go into Iraq, vision. Meanwhile, Dr. Ben Carson trying to clarify what he meant when he said he would not support a Muslim becoming president. I have subsequently said if it was a Christian running for president but they wanted to impose a theocracy I would not support that either. Why would a Muslim not do that. Traditionally Islam does not separate church and state. So they obviously are going to have to do a fairly significant departure from what they traditionally do which is fine. Reporter: Now, Dr. Carson tells me his campaign has reached out to muslim-american groups to discuss any issues they have and, robin, if you were wondering, Donald Trump still hates Fox News's megyn Kelly calling her a lightweight on Twitter and should take another vacation.
This transcript has been automatically generated and may not be 100% accurate.