Trump White House sends formal threat to John Bolton -- and warns him not to publish his book: CNN
John Bolton appears on ABC (screen grab)

CNN is reporting that the Trump White House has sent a formal threat to former national security adviser John Bolton aimed at blocking the publication of his upcoming tell-all book about his time working for the president.

The threat against Bolton marks an escalation for the Trump White House, which has resisted allowing Bolton to testify in the president's Senate impeachment trial. The president himself attacked Bolton in a tweet on Wednesday morning, and claimed that he fired him as national security adviser because he wanted to start "World War Six."

It is unclear how successful this ploy will be, however, as the president in 2018 unsuccessfully sued to stop the publication of Michael Wolff's insider book "Fire and Fury," which contained multiple embarrassing revelations about the Trump White House.