In an early morning tweet, Trump accused the “failing New York Times” of “setting up” Corker, a reference to a scathing interview published Sunday night in which Corker expressed deep misgivings about Trump, questioned his stability as president, and worried that his threats would launch the U.S. into “World War III.”

The Failing @nytimes set Liddle' Bob Corker up by recording his conversation. Was made to sound a fool, and that's what I am dealing with! — Donald J. Trump (@realDonaldTrump) October 10, 2017

Trump on Tuesday said the paper made “Liddle Bob Corker... sound a fool, and that’s what I am dealing with!” — tagging the senator with a nickname that appeared to refer to Corker’s height.

The Times reported that Corker made his acid comments “carefully and purposefully,” and that he “seemed to almost find cathartic satisfaction by portraying Mr. Trump in terms that most senior Republicans use only in private.”

Though Trump’s tweet complained that the paper recorded Corker’s interview, Times reporter Jonathan Martin, who shared a byline on the Corker story, said the senator also recorded the conversation.

Once a prominent Trump supporter, Corker in recent months has increasingly expressed concerns about Trump’s presidency.

After Trump’s failure to forcefully condemn white supremacists who unleashed violence in Charlottesville, Virginia, over the summer, Corker said the president “has not yet been able to demonstrate the stability nor some of the competence that he needs to demonstrate in order to be successful.”

Trump’s public sparring with the powerful GOP senator began Sunday morning, when he accused Corker of “begging” for a re-election endorsement. Corker, who has said he won’t seek re-election, denied the claim, and his office said it was Trump who urged Corker not to step down.

Corker tweeted: “It’s a shame the White House has become an adult day care center. Someone obviously missed their shift this morning.”

Trump’s antagonism toward Corker and other top GOP lawmakers risks his legislative agenda. Corker is chairman of the influential Senate Foreign Relations Committee. He’s also a member of the Budget Committee, where he will likely help draft tax reform legislation, which is shaping up to be Trump’s next fight in Congress.