President Donald Trump told his former national security adviser John Bolton in August that he wanted to freeze $391 million in U.S. aid to Ukraine until their government agreed to investigate Democrats including the Biden family, according to an unpublished draft of a new book written by Bolton.

Trump denied Bolton’s claim early Monday morning, writing it off as a publicity effort for his upcoming book.

“I NEVER told John Bolton that the aid to Ukraine was tied to investigations into Democrats, including the Bidens,” wrote Trump. “In fact, he never complained about this at the time of his very public termination. If John Bolton said this, it was only to sell a book.”

Bolton provided a copy of the book to the White House on Dec. 30 so it could be reviewed for any classified information, though Bolton believed it contained none.

Bolton’s lawyer, Charles Cooper, believed the White House inappropriately disclosed the book’s contents to media as it was under review.

“It is clear, regrettably, from the New York Times article published today that the pre-publication review process has been corrupted and that information has been disclosed by persons other than those properly involved in reviewing the manuscript,” Cooper said Sunday night.

In the transcript, Bolton described his involvement in the Ukraine affair, as well as Trump’s direct role in directing the pressure campaign.

Trump was impeached in December after a House investigation concluded he abused his power by pressuring the government of campaign to open an investigation into his political rival, Joe Biden, and subsequently obstructed Congress in a cover-up effort.

Bolton also highlighted other senior administration officials’ roles and private opinions about the affair.

He wrote that Secretary of State Mike Pompeo privately contradicted Trump’s personal attorney, Rudy Giuliani‘s, claim that the ambassador to Ukraine was corrupt and thought Giuliani may have been acting on behalf of other clients.

Bolton wrote that the acting White House chief of staff, Mick Mulvaney, was present for at least one phone call where the president and Giuliani discussed the ousted ambassador. Mulvaney previously claimed he was never a part of the calls, as those were protected by their attorney-client privilege.

Bolton also said that he told Attorney General William Barr about Trump’s July 25 phone call with Ukraine, in which he requested the foreign leader to “look into” Biden. A spokeswoman for Barr denied that he was told about the call by Bolton, and the Justice Department said it only learned about it in mid-August.

The House impeachment managers argued that Bolton’s transcript provided a clear need for his testimony in the trial.

“There can be no doubt now that Mr. Bolton directly contradicts the heart of the president’s defense,” they said in a statement.

Bolton has previously indicated he would be willing to testify if subpoenaed, but Democrats must convince the GOP-majority Senate why his testimony is critical.