President Donald Trump believed Russian President Vladimir Putin over his own intelligence agencies on North Korea, former Deputy FBI Director Andrew McCabe said in his new book, "The Threat," according to The Washington Post.

North Korea tested its first intercontinental ballistic missile on July 4, 2017.

Trump insisted intelligence reports that North Korea had launched an ICBM were incorrect because Putin had told him that North Korea did not have that capability, the book says, per The Post.

The president has repeatedly clashed with the US intelligence community on a wide range of issues.

When US intelligence officials informed President Donald Trump that North Korea had tested an intercontinental ballistic missile, he reportedly refused to believe them.

Instead, he relied on questionable information given to him by Russian President Vladimir Putin, according to a new book by former Deputy FBI Director Andrew McCabe, The Washington Post reported Thursday.

North Korea tested its first ICBM — the Hwasong-14 — on July 4, 2017, shocking the world by demonstrating advanced capabilities beyond what many believed possible for the rogue country.

Read more: North Korea's missile took a bizarre path through space, and here's why it deeply worries weapons experts

Trump reportedly dismissed the supposed launch of an ICBM as a "hoax," McCabe said in his book, "The Threat," due out Tuesday.

"He thought that North Korea did not have the capability to launch such missiles. He said he knew this because Vladimir Putin had told him so," McCabe wrote, according to The Post.

The Trump administration later acknowledged that North Korea had, in fact, launched an ICBM.

North Korea would go on to launch another Hwasong-14 ICBM later that month. That November, it test-fired the significantly more powerful Hwasong-15 ICBM. Experts said they suspected the first's range included cities on the US's West Coast, while the second could theoretically strike anywhere in the continental US.

Putin, however, remained unconvinced.

Russia refused to acknowledge that North Korea had tested an ICBM, with Russian media reports referring to intermediate-range ballistic missiles. Russia may have made its assessment for political reasons, or perhaps its early-warning systems failed to detect the missile's second stage, The Diplomat reported.

The insider account told by McCabe, who clashed with Trump before he was fired last March, is disconcerting yet appears consistent with the president's past behavior. McCabe joined the FBI in 1996 and worked in the Counterterrorism Division and the National Security Branch, among other postings.

The president has repeatedly disputed and rebuked his intelligence officials on Russia's attempts to influence the 2016 US presidential election. He recently lashed out at officials who had testified before Congress and contradicted him on North Korea, Iran, and the terrorist group ISIS.

In a tweet, he insisted the US intelligence community is "naive," adding: "They are wrong! Perhaps Intelligence should go back to school!"

Read more: 'Perhaps Intelligence should go back to school!': Trump lashes out at his intel chiefs after they contradict his views on global threats

McCabe's book reportedly attempts to highlight Trump's apparent subservience to Russia. The White House, however, has argued that McCabe "has no credibility and is an embarrassment to the men and women of the FBI and our great country."