U.S. President Donald Trump (R) and Prime Minister of Japan Shinzo Abe walk out from the Oval Office before their joint news conference in the Rose Garden of the White House on June 7, 2018 in Washington, DC.
CNN  — 

Former Japanese Prime Minister Shinzo Abe urged then-President Donald Trump not to relent with North Korea and to keep up the threat of military pressure, according to his memoir.

In his posthumously published book “Abe Shinzo: Kaikoroku,” Abe details his meetings with Trump and exposes the then-president’s thought process when it came to negotiations with North Korea and strategic defense matters in Asia.

“I kept telling him, ‘What Kim Jong Un fears most is that suddenly a Tomahawk shot will cost him his life, his family’s life. I kept telling Trump that only the US can put pressure on him to use force,’” Abe writes in his Japanese language memoir, according to an English translation.

Abe recalled that there were concerns that Trump would convey to Kim, the North Korean leader, that he was reluctant to take military action, and both Abe and Trump’s national security team were keen to make sure that the world did not find out about it.

“If Kim Jong Un finds out that Trump is someone who is reluctant to take military action, then the pressure will be off. So we had to make absolutely sure that the outside world was not aware of it. We had to make the North Koreans think, ‘If it comes to Trump, he’ll do it.’ Not only me but also the US security team was desperate to keep Trump’s true nature under wraps,” Abe writes.

In his memoir, Abe shares that he told Trump that North Korea should destroy “not only nuclear weapons but also ICBMs, medium-range missiles and biological weapons … but he did not listen. For him, diplomacy is a new field and he has not been involved in North Korean affairs for many years. The US State Department, the White House security team and I could not stop Trump from thinking about making history.”

John Bolton, who was Trump’s national security adviser at the time, confirmed Abe’s account and said the late prime minister repeatedly emphasized the importance of portraying a US military threat to Kim. Bolton said he and his Japanese counterpart were in regular contact throughout his tenure.

“There’s no chance that you get North Korea to denuclearize if they think there’s no military threat and Abe said that to Trump in every meeting he had with him,” Bolton told CNN. “I’m grateful for the reference, but I don’t think it took us for Abe to understand what he needed to do. And he was absolutely right. Trump needed to hear it repeatedly.”

Trump’s team did not return request for comment.

Trump has repeatedly said that his “maximum pressure” strategy with North Korea is what brought Pyongyang to the negotiating table during his presidency, though no deal on denuclearization was ever reached.

Abe said that one of Trump’s powers in negotiating was that he was seen as the person on the international stage who would be most likely to use military force. “I think people are wary that Trump is the type of person who would suddenly use military force in the international community,” he writes.

If those actions would cost the US a lot of money, though, Trump was unlikely to react the same way, according to the former prime minister.

“He is a businessman at heart, so he was cautious about things that cost money. He thinks about diplomacy and security in terms of money,” Abe writes.

“When the US military dispatched an aircraft carrier strike group around the Sea of Japan in 2017, Trump initially asked me, ‘Do you know how much it costs to move an aircraft carrier? I don’t like it.’ He said, ‘I would rather keep the aircraft carrier in the military port,’” Abe writes.

Trump was also reluctant to keep funding military drills with South Korea, Abe writes, quoting Trump as saying, “The joint military exercises between the US and South Korea cost a huge amount of money. It is a waste. It should be stopped.”

Abe thought this would have an effect on negotiations at the US-North Korea summit and told Trump: “We can’t have the US troops in South Korea withdrawn, if you are going to have a US-North Korea summit.”

The book – released this week – contains interviews that were conducted by two journalists from October 2020 to October 2021. Abe died in July 2022 after being shot while giving a campaign speech on a street in central Japan. The book was originally scheduled to be published a year ago. However, the book reveals that Abe had requested that the publication be postponed as it was too sensitive. It is said that his wife, Akie Abe, agreed to the memoir’s publication.

CNN’s Kristen Holmes contributed to this report.