WASHINGTON — President Trump denounced his former secretary of state, Rex W. Tillerson, as "dumb as a rock" and "lazy as hell" on Friday after the ex-cabinet member said that the president had regularly pushed him to take actions that were illegal.

Mr. Trump, who fired Mr. Tillerson with a Twitter post in March, fired back at him in the same social media channel after the former secretary gave a talk in Houston breaking his silence. In the talk, Mr. Tillerson said Mr. Trump was undisciplined, did not like to read and did not respect the limits of his office.

"Mike Pompeo is doing a great job, I am very proud of him," Mr. Trump wrote on Friday afternoon, referring to the current secretary. "His predecessor, Rex Tillerson, didn't have the mental capacity needed. He was dumb as a rock and I couldn't get rid of him fast enough. He was lazy as hell. Now it is a whole new ballgame, great spirit at State!"

The president did not say so but appeared to be responding to comments Mr. Tillerson made in Houston on Thursday night during a public discussion with Bob Schieffer, the longtime CBS News journalist, at an event benefiting M.D. Anderson Cancer Center.

Mr. Tillerson, a former Exxon Mobil chief executive, for the most part has stayed out the public eye since his departure from the Trump administration but unloaded under questioning by Mr. Schieffer.

"It was challenging for me coming from the disciplined, highly process-oriented Exxon Mobil Corporation to go to work for a man who is pretty undisciplined, doesn't like to read, doesn't read briefing reports, doesn't like to get into the details of a lot of things, but rather just kind of says, 'Look, this is what I believe,' " Mr. Tillerson said.

Mr. Tillerson said the president kept pressing for actions beyond his authority.

"So often, the president would say here's what I want to do and here's how I want to do it and I would have to say to him, 'Mr. President, I understand what you want to do but you can't do it that way,' " Mr. Tillerson said. "It violates the law."The former secretary said the president would get frustrated. "I'd say, 'Here's what we can do. We can go back to Congress and get this law changed. And if that's what you want to do, there's nothing wrong with that,'" Mr. Tillerson said. "I told him, 'I'm ready to go up there and fight the fight, if that's what you want to do.' "

"I will be honest with you, it troubles me that the American people seem to want to know so little about issues, that they are satisfied with a 128 characters," Tillerson told Schieffer.

Mr. Trump's response about Mr. Tillerson's intelligence repeats a theme for him. After news reports that Mr. Tillerson once called the president a "moron" (or an expletive-deleted moron, depending on the account), Mr. Trump challenged him to an I.Q. contest. "And I can tell you who is going to win," the president insisted.

Peter Baker, December 7, 2018

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December 8, 2018

Post Script.The rats are jumping ship. Let's get this guy out! #RemoveTrum