The Times further claimed Bolton had shared a manuscript of his forthcoming book with "close associates" -- prompting Bolton's team to deny the claim, and assert that the National Security Council's [NSC's] review process of pending manuscripts is "corrupted" and prone to leaks.

A "pre-publication review" at the NSC, which functions as the White House's national security forum, is standard for any former government officials who held security clearances and publicly write or speak publicly about their official work. The review typically would focus on ferreting out any classified or sensitive material in advance of publication, and could take from days to months.

Trump fired back on Twitter on Sunday to refute Bolton's claims, saying he "NEVER told John Bolton that the aid to Ukraine was tied to investigations into Democrats, including the Bidens." Trump went on to accuse Bolton of trying to "sell a book," noting that Bolton did not complain publicly or privately about the aid holdup "at the time of his very public termination."

...transcripts of my calls with President Zelensky are all the proof that is needed, in addition to the fact that President Zelensky & the Foreign Minister of Ukraine said there was no pressure and no problems. Additionally, I met with President Zelensky at the United Nations...

— Donald J. Trump (@realDonaldTrump) January 27, 2020

...(Democrats said I never met) and released the military aid to Ukraine without any conditions or investigations - and far ahead of schedule. I also allowed Ukraine to purchase Javelin anti-tank missiles. My Administration has done far more than the previous Administration.

— Donald J. Trump (@realDonaldTrump) January 27, 2020

The New York Times is reporting that John Bolton’s book will implicate el Presidente as tying military aid to Ukraine to investigating the Bidens.

Breaking News: President Trump said he wanted to keep aid to Ukraine frozen until its officials helped him with investigations into Democrats, John Bolton wrote in an unpublished manuscript of a new book https://t.co/J1tJ5oPZAY

— The New York Times (@nytimes) January 26, 2020

President Trump told his national security adviser in August that he wanted to continue freezing $391 million in security assistance to Ukraine until officials there helped with investigations into Democrats including the Bidens, according to an unpublished manuscript by the former adviser, John R. Bolton.

The president’s statement as described by Mr. Bolton could undercut a key element of his impeachment defense: that the holdup in aid was separate from Mr. Trump’s requests that Ukraine announce investigations into his perceived enemies, including former Vice President Joseph R. Biden Jr. and his son Hunter Biden, who had worked for a Ukrainian energy firm while his father was in office.

Mr. Bolton’s explosive account of the matter at the center of Mr. Trump’s impeachment trial, the third in American history, was included in drafts of a manuscript he has circulated in recent weeks to close associates. He also sent a draft to the White House for a standard review process for some current and former administration officials who write books.

Multiple people described Mr. Bolton’s account of the Ukraine affair.