White House official told whistleblower Trump Ukraine call was 'frightening' Notes suggest at least one person close to Trump was alarmed.

A White House official listening to President Donald Trump’s July 25 phone call with Ukraine’s president described the call as “crazy” and “frightening” and was “visibly shaken,” according to notes taken by the intelligence official who filed a formal whistleblower complaint after speaking with the official, and others.

ABC News has learned that the two-page memo, written by the whistleblower a day after Trump’s call, suggests that at least one aide to the president feared that Trump’s own words in the call were damning. According to a rough transcript of the call released by the White House, Trump asked Ukraine’s president Volodymyr Zelenskiy to launch an investigation into a political opponent, Democratic presidential candidate Joe Biden, and his son.

The notes were based on a brief conversation between the whistleblower and the White House official and described “highlights” from the president’s call. The document was later provided to the intelligence community’s inspector general, who reviewed the whistleblower’s complaint. The IG has determined the complaint “appeared credible” and of “urgent concern.”

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The White House had not responded to a request for comment. Trump has defended the call as acting on his duty as president to end corruption “even if that means requesting the help of a foreign country or countries.”

“This has NOTHING to do with politics or a political campaign against the Bidens,” Trump tweeted Oct. 4. This does have to do with their corruption!”

Trump also has dismissed the whistleblower’s account of the phone call because he says the complaint was based on second-hand information. According to the IG report, the individual had both first and second-hand information. This week a second whistleblower has come forward with what that person’s lawyer describes as first-hand knowledge.

“The President urged Zelenskiy to investigate the Bidens and stated that [Trump's personal attorney Rudy] Giuliani would discuss this topic further with Zelenskiy during his trip to Kyiv,” the unnamed White House official told the first whistleblower, according to the notes.

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"The official, who listened to the entirety of the phone call, was visibly shaken by what had transpired and seemed keen to inform a trusted colleague within the U.S. national security apparatus about the call," the whistleblower writes in the memo.

The memo states the official "described the call as "crazy," "frightening," and completely lacking in substance related to national security."

After the call, the whistleblower says "I ... returned to my office, and wrote up my best recollection of what I had heard." The person notes that they did not review the call transcript or written notes, “but the official informed me they exist.”

The official recalled to the whistleblower that the president also asked the Ukranian leader about "Crowdstrike server" a reference to a debunked theory that Ukraine is holding Hillary Clinton's missing emails, and that it was the Ukraine, not Russia, that was behind the interference in the 2016 election.

The White House official also correctly recalled that the president raised the issue of Burisma holdings, a company that employed Vice President Joe Biden's son, Hunter Biden.

Importantly, the whistleblower also documented suspicions from the White House official that notes or transcripts from the call were being protected in an unusual manner. ABC News has reported that the White House changed its practice of storing phone call transcripts with foreign leaders to avoid leaked by keeping them in secure servers with restricted access. It was unclear if those conversations, however, were being protected for reasons of national security or for political reasons.