The White House says that former national security adviser John Bolton's book contains top secret information in a letter addressed to his attorney that was publicly released Wednesday.

The state of play: The development, first reported by CNN's Jake Tapper, sets up a potential legal battle between Bolton and the White House over the book's publication, which is currently scheduled for March 17.

The letter, dated Jan. 23, claims the book contains "significant amounts of classified information" that could "cause exceptionally grave harm" to U.S. national security.

It was signed by Ellen Knight, the National Security Council's senior director for records, access and information security management.

The letter says, "the manuscript may not be published or otherwise disclosed without the deletion of this classified information" and that the White House will be in touch with "additional, more detailed guidance regarding next steps" on how to move forward.

The big picture: It comes amid an ongoing battle over whether to call Bolton as a witness in President Trump's Senate impeachment trial after the manuscript's account of the Ukraine saga leaked to the New York Times.

Trump chimed in regarding Bolton on Twitter Wednesday, saying the U.S. "would be in World War Six by now" if he had listened to his former national security head during his tenure.

The president also foreshadowed this decision about Bolton's "nasty & untrue" book, which was submitted last month to the White House for pre-publication review, claiming it contained "All Classified National Security."

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