George Kent, deputy assistant U.S. secretary of state, arrives for closed-door testimony before House committees on Capitol Hill in Washington, D.C., U.S., on Tuesday, Oct. 15, 2019.

WASHINGTON – President Donald Trump "wanted nothing less than [Ukrainian President Volodimyr] Zelensky to go to microphone and say 'investigations, Biden and Clinton,'" a State Department official told congressional investigators conducting an impeachment probe.

The account of George Kent, the deputy assistant secretary for European and Eurasian Affairs, was released as a transcript Thursday. It further underscored how specific the Trump administration's alleged demands of the Ukrainian government were.

It also added to the growing body of evidence of a quid-pro-quo orchestrated by the White House, whereby military aid to Ukraine would be withheld until the Ukrainian president agreed to publicly say what Trump wanted him to.

Kent, however, said that while he understood what the president wanted, at the time, he was not aware of what was being offered by the White House in exchange.

Current and former national security officials, including Trump-appointed ambassador to the E.U. Gordon Sondland, have testified that the president was withholding nearly $400 million of congressionally appropriated military aid to Ukraine until Zelensky publicly announced the investigations Trump and his attorney, Rudy Giuliani, wanted.

Kent's 355-page testimony, made on October 15, is the latest in a string of testimonies released this week by House Democrats overseeing the impeachment inquiry.

The House will begin holding public testimony in the impeachment probe next week.

Kent also described learning earlier this year that Giuliani had met with a controversial Ukrainian prosecutor who sought to "throw mud" at both Kent and at the U.S. ambassador to Ukraine, Marie Yovanovitch.

Kent testified that he learned on July 18 that Trump had placed a hold on all military aid to Ukraine, one week before the July 25 phone call between Trump and Zelensky.

"It was described as a hold, not a freeze," Kent said. He then explained how a relatively low-level aide at the Office of Management and Budget suddenly appeared on a Ukraine-focused video conference call on July 18, and told the diplomats on the call that the acting White House chief of staff, Mick Mulvaney, "at the direction of the president, had put a hold on all security assistance to the Ukraine."

Kent also said he learned of several Republican senators who contacted the president in an attempt to convince the administration to lift the hold on Ukraine aid.

"I am aware that many senators, particularly from the Republican side, who had traveled to Ukraine from the relevant committees, called and talked to the president," Kent told investigators. "I'm aware that I saw an email that Sen. Jim Inhofe [of Oklahoma] had had about a 20-minute conversation. He had visited twice when I was in Ukraine....[Ohio Sen.Rob] Portman called, including on the day it was lifted," Kent said. "And my understanding is that Senate Majority Leader [Mitch] McConnell also called."

A spokesman for the Kentucky Republican did not immediately respond to an email from CNBC requesting confirmation and more information about any calls McConnell and the president had about Ukraine.

Trump has previously claimed that McConnell told him his July 25 phone call with Zelensky was "perfect." McConnell, however, denied having spoken to Trump about the call. "I don't recall any conversations with the president about that phone call," McConnell recently told reporters.

The House investigation focuses on whether Trump abused the power of his office in his attempt to pressure Ukraine to investigate the son of his political rival, former Vice President Joe Biden. And if so, whether those actions meet the standard for "high crimes and misdemeanors" deserving of impeachment and, potentially, removal from office.