Former National Security Advisor John Bolton said Thursday that Trump administration officials who testified in the House impeachment investigation should be free to speak out without “retribution.”

Bolton argued that former and current officials, including acting U.S. Ambassador to Ukraine Bill Taylor, National Security Council member Alexander Vindman, and fired U.S. Ambassador to Ukraine Marie Yovanovitch, were right to tell lawmakers what they knew about President Donald Trump’s dealings with Ukraine.

“All of them acted in the best interest of the country as they saw it and consistent to what they thought our policies were,” Bolton said during a private event hosted by Luther King Capital Management in Austin, Texas, reports KXAN. “The idea that somehow testifying to what you think is true is destructive to the system of government we have — I think, is very nearly the reverse — the exact reverse of the truth.”

Bolton’s remarks come after the New York Times reported that the former national security advisor’s forthcoming book — The Room Where It Happened: A White House Memoir — alleges that President Trump sought to tie U.S. security assistance to Ukraine to inquiries into allegations of corruption against former Vice President Joe Biden and his son, Hunter Biden.

President Trump has vehemently denied the reported allegations as “false” and took to Twitter to bash Bolton as disloyal.

“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 [sic] 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,” tweeted the president. “All Classified National Security. Who would do this?”

This story is developing. Check Breitbart News for updates.