Former national security adviser John Bolton, speaking out for the first time since the conclusion of President Donald Trump's impeachment trial, discussed his upcoming book and expressed serious concerns about the White House review process that he claimed is holding up its publication.

Bolton labeled the review process as "censorship."

"I say things in the manuscript about what [Trump] said to me; I hope they become public someday," Bolton said during an interview in front of an audience at Duke University on Monday evening. "He tweets, but I can't talk about it -- how fair is that?"

Bolton's book, which contains allegations regarding President Trump's personal involvement with activities in Ukraine that led to his impeachment and subsequent acquittal, has been in a standard prepublication security review for classified information with the White House National Security Counsel since December 30th, according to Bolton's lawyer, Charles Cooper.