June 18 (UPI) -- Former national security adviser John Bolton, who is highly critical of President Donald Trump in an upcoming book, said in an interview broadcast Thursday his former boss and commander in chief is incompetent and unfit for office.
Bolton told ABC News that Trump, for whom he served as national security adviser for 17 months, is primarily motivated in his actions as president by winning a second term.
"There really isn't any guiding principle that I was able to discern other than what's good for Donald Trump's re-election," he said in the interview.
"He was so focused on the re-election that longer-term considerations fell by the wayside."
The Bolton interview is part of an ABC News program scheduled for broadcast Sunday.
Bolton's book, The Room Where It Happened, is set for release on Tuesday. In it, Bolton makes several accusations against the president, including that he's "stunningly uninformed," does not know basic facts and is easily manipulated by foreign leaders.
Bolton also said in the interview that Trump's interactions with foreign policy caused him great concern, particularly a historic summit with North Korean leader Kim Jong Un in 2018.
"I was sick at heart over Trump's zeal to meet with Kim," he said. "There was considerable emphasis on the photo opportunity and the press reaction to it and little or no focus on what such meetings did for the bargaining position of the United States."
Trump has called Bolton "a liar" and said he fired him as national security adviser. Bolton, who clashed with Trump and other advisers before leaving the White House last September, counters that he resigned.
Bolton's interview came after heightened efforts by the Justice Department to block the upcoming book. The department appealed to a judge late Wednesday, saying the memoir contains potentially harmful classified information, and asked for a hearing Friday.