The White House has asked former National Security Advisor John Bolton to delay the release of his forthcoming book, citing “significant amounts of classified information” contained in the manuscript.

In a letter dated January 23, Ellen Knight — who serves as the National Security Council’s Senior Director for Records, Access, and Information Security Management — wrote to Bolton’s attorneys that the classified information contained in The Room Where It Happened: A White House Memoir make it unsuitable for release and requested that the sensitive details be removed.

“Under federal law and the nondisclosure agreements your client signed as a condition for gaining access to classified information, the manuscript may not be published or otherwise disclosed without the deletion of this classified information,” Knight wrote to lawyer Charles Cooper.

Knight also wrote that a preliminary review found some of the upcoming book contains “top secret” information and would provide additional guidance after the NSC concluded its ongoing examination of the text. “We will do our best to work with you to ensure your client’s ability to tell his story in a manner that protects U.S. national security,” wrote the Trump official.

The letter was sent to Cooper three days after the New York Times reported that Bolton’s book alleges President Trump wanted U.S. military aid to Ukraine to be conditional on inquiries into allegations of corruption against former Vice President Joe Biden, and his son, Hunter Biden. The president has denied the report as “false” and took aim at his former top foreign policy in a pair of tweets earlier Wednesday.

“For a guy who couldn’t get approved for the Ambassador to the U.N. years ago, couldn’t get approved for anything since, ‘begged’ me for a non Senate approved job, which I gave him despite many saying ‘Don’t do it, sir,’ takes the job, mistakenly says ‘Libyan Model’ on T.V., and many more mistakes of judgement [sic], gets fired because frankly, if I listened to him, we would be in World War Six by now, and goes out and IMMEDIATELY writes a nasty & untrue book. All Classified National Security. Who would do this?” the president wrote.

The development has prompted renewed calls from Democrats to call Bolton as a witness in the Senate impeachment trial, though several reports indicate that Senate Majority Leader Mitch McConnell (R-KY) has the votes to block additional witnesses from testifying. Some Senate Republicans are already signaling that the upper chamber may move swiftly to acquit President Trump as early as Friday.

“That’s the plan,” Sen. John Barrasso (R-WY) replied when asked if an aquatical vote could be quickly called if Democrats fail to clinch the votes required for more witnesses. Sen. Lindsey Graham (R-SC) told Fox News on Tuesday that “the president will be acquitted, and I think it will be this week.”

“This is the weakest case you’ll ever see in the history of the country in terms of impeachment,” he added.