Transcript for Trump continues his name calling and Twitter war with Sen. Bob Corker
and the war of words. President trump taking aim at Republican senator Bob corker. It was corker who told "The new York Times" the president's actions risk World War III. And after secretary of state Rex tillerson is reported to have called the president a moron, the president seemed to challenge Rex tillerson today to an iq test. Here's ABC's chief white house correspondent Jonathan Karl. Reporter: President trump seemed to lob a new insult at his secretary of state today, after that report Rex tillerson called him a, quote, moron. "I think it's fake news," the president told Forbes, "But if he did that, I guess we'll have to compare iq tests. And I can tell you who is going to win." The president was asked today if he is undercutting his own secretary of state. No, I didn't undercut anybody. I don't believe in undercutting people. Thank you very much, everybody. Do you still have confidence in secretary tillerson, sir? Yes. Reporter: But the new comments come after the president said he'd like tillerson to be, quote, "A little bit tougher." Why would the presidentp want someone tough, nor particularly smart as secretary of state? The president certainly never implied that secretary of state was not incredibly intelligeintelligent. He made a joke, nothing more than that. He doesn't realize that, you know, that we could be heading towards World War II with the kinds of comments that he's making. Reporter: The failing "New York Times" set little Bob corker up by recording his conversation, the president tweeted today. Was made to sound a fool, and that's what I am dealing with. But we're now learning it was, in fact, corker who asked "The New York Times" to record the interview. And tonight, two Republican senators, the only two so far, have come forward to criticize corker and defend the president. David, both of those senators are up for re-election. Jon Karl live in Washington. Jon, thank you.
This transcript has been automatically generated and may not be 100% accurate.