President Donald Trump took to Twitter on Wednesday to attack former National Security Advisor John Bolton for his latest allegations in an unpublished book. 

Bolton’s book contradicts a key element of the president’s impeachment defense, claiming that Trump personally told him he didn’t want to release military aid to Ukraine until they cooperated with investigations to uncover damaging information on Democrats, including former Vice President Joe Biden. 

Trump’s tweets claimed that if Bolton were still the National Security Advisor, that the United States “would be in World War Six by now.”

This came hours after another tweet in which Trump asked: “Why didn’t John Bolton complain about this ‘nonsense’ a long time ago, when he was very publicly terminated.”

Bolton has denied being terminated and maintains he resigned.

Earlier this week, reports surfaced that an unpublished version of an upcoming book by Bolton held transcripts of conversations that show that Trump said nearly $400 million in aid to Ukraine would be frozen until they provided information in connection with the investigations of Democrats the president requested in a July phone call.

Trump’s defense team has argued that the hold on aid and the request for an investigation into Democrats were not connected. John Kelly, former Chief of Staff, said Monday that he believes the claims made in Bolton’s book and thinks the Senate should allow for additional witnesses in the Senate trial.

“If John Bolton says that in the book, I believe John Bolton,” said Kelly.