Secretary of State Mike Pompeo doubted Trump lawyer Rudy Giuliani's claims that former United States Ambassador to Ukraine Marie Yovanovitch was corrupt, according to a draft of former national security adviser John Bolton's book.

Drafts of Bolton's unpublished book said Pompeo privately admitted to him last spring that Giuliani may have been pushing baseless accusations about Yovanovitch because she may have been cracking down on Giuliani's clients with dealings in Ukraine as part of an anti-corruption effort, according to the New York Times.

Bolton, who left the White House in September, also wrote that President Trump told him in August that he was withholding nearly $400 million in congressionally approved military aid to Ukraine until Kyiv assisted with investigations into his political rivals, including former Vice President and presidential candidate Joe Biden. Bolton, Pompeo, and Defense Secretary Mark Esper repeatedly pushed Trump to unlock the funds, which were released in September.

In a salvo of tweets just after midnight on Monday, Trump denied telling Bolton that the security aid to Ukraine was tied to investigations. "If John Bolton said this, it was only to sell a book," he said.

Bolton announced earlier this month that he is willing to testify in the Senate impeachment trial if called by lawmakers, but Trump has indicated that he will block Bolton from testifying.

Democrats have wanted Bolton to testify ever since his former aide, Fiona Hill, testified to House impeachment investigators that Bolton opposed the Ukraine pressure campaign. She said Bolton wanted no part of what he described as a "drug deal" that fellow Trump administration officials were "cooking up."

The New York Times report, based on drafts circulating among Bolton's associates and the White House for a review process, comes two days after NPR host Mary Louise Kelly said Pompeo shouted and swore at her when she asked him about Ukraine and whether he had ever defended Yovanovitch and owed her an apology.

Pompeo released a statement accusing Kelly of lying to him and reporting the details of a conversation he claimed was off the record.

[READ: Democrats argue 'explosive' details from Bolton book demand his impeachment testimony]

"This is another example of how unhinged the media has become in its quest to hurt President Trump and this Administration. It is no wonder that the American people distrust many in the media when they so consistently demonstrate their agenda and their absence of integrity," he said.

Yovanovitch was recalled from her post in May 2019 and went on to testify in the House impeachment hearings that a superior told her that she had done nothing wrong, but that Trump had lost faith in her. She also condemned the “smear campaign” against her, saying allegations that she put together a “Do Not Prosecute” list were a “fabrication” and denying claims that she had told anyone at the embassy or in Ukraine that Trump’s orders should be ignored.

Michael McKinley, another impeachment witness who was a top adviser to Pompeo, testified that his former boss rejected his push for the State Department to release a statement supporting Yovanovitch and highlighting her "professionalism and courage." Pompeo claimed afterwards that McKinley, who abruptly resigned in October, "didn't say anything to me" about it.

[READ: Bolton lawyer blames book leak on 'corrupted' review process]

Trump had called for Yovanovitch's ouster as early as April 2018 during a private dinner that was attended by two now-indicted associates of Giuliani.

"Get rid of her. Get her out tomorrow. I don't care. Get her out tomorrow. Take her out. OK? Do it," the president can be heard saying in the footage taken by Igor Fruman, who along with Lev Parnas informed the president that the ambassador had been talking badly about him.

Bolton's book, published by Simon & Schuster, will also touch on controversies related to Russia and Venezuela, and some top Trump officials are said to be subject to unkind descriptions. According to the latest report, Bolton claimed he raised concerns about Giuliani with Attorney General William Barr after Trump's July 2019 phone call with Ukrainian President Volodymyr Zelensky.

A transcript of the call that was released to the public shows Trump encouraged Zelensky to talk to Giuliani and Barr about investigations into Democrats. A statement by the Justice Department claimed Trump never told Barr to contact Ukraine about said inquiries and distanced the attorney general from Giuliani.

Bolton's book, titled The Room Where it Happened, is tentatively scheduled to be released on March 17.