WASHINGTON - House Speaker Nancy Pelosi, D-Calif., said Thursday that testimony presented by two career diplomats during Wednesday's open impeachment hearing "corroborated evidence of bribery" by President Donald Trump in his relations with Ukraine.

Her comments came as Democrats seek to build a case that Trump sought to withhold military assistance and an Oval Office meeting until Ukraine announced investigations into former vice president Joe Biden and his son Hunter Biden, as well as an unfounded theory that Ukrainians interfered in the 2016 presidential election to hurt Trump.

House Intelligence Committee Chairman Adam Schiff, D-Calif., floated the idea that Trump committed bribery two days ago.

"On the basis of what the witnesses have had to say so far, there are any number of potentially impeachable offenses, including bribery, including high crimes and misdemeanors," Schiff said in an interview with NPR on Tuesday.

At her news conference, Pelosi forcefully pushed back against the efforts by Trump and his allies to dismiss as "secondhand" Wednesday's testimony by acting ambassador to Ukraine William Taylor and Deputy Assistant Secretary of State George Kent

"That is such a fraudulent proposition put forward by the Republicans," Pelosi said. "We are not here to be manipulated by the obstruction of justice of the administration."

Taylor testified Wednesday that a member of his staff overheard Trump referring to "the investigations" in a telephone call with Sondland on July 26. That was a day after the call between Trump and Zelensky, in which Trump had pressed for investigations into the Bidens.

The revelation of that call potentially implicates Trump more directly in a scheme to center U.S. policy toward Ukraine on political investigations.

Trump told reporters on Wednesday that he had no recollection of the call. House investigators expect to hear in a closed-door session Friday from David Holmes, the counselor for political affairs at the U.S. Embassy in Kyiv, who is said to have overheard the call.

Meanwhile, Ukraine's Foreign Minister Vadym Prystaiko says his conversations with Gordon Sondland, the U.S. ambassador to the European Union, did not include explicit mention linking U.S. military aid with possible investigations of the Bidens.

Prystaiko, however, commented only on his direct interactions with Sondland, whose reported phone call with Trump in late July has emerged as a new and potentially important element in the impeachment inquiries.

"Ambassador Sondland did not tell us, and certainly did not tell me, about a connection between the assistance and the investigations. You should ask him," Prystaiko was quoted as saying by the Interfax Ukraine news agency.

Earlier Thursday, Trump asserted that "normal people" would close the case on his impeachment after Wednesday's nationally televised hearing.

His assessment underscored the clash that emerged after the six-hour hearing, with Democrats saying it provided damning evidence of a president using his office to advance his political interests, while Republicans argued it laid bare a desperate attempt to oust Trump from office.

White House counselor Kellyanne Conway said Thursday that the impeachment inquiry amounts to an attempt by Democrats to "interfere" in the 2020 election as she assessed Wednesday's hearing during a television appearance.

"They can't get him at the ballot box," Conway said on Fox News' "Fox & Friends." "They're trying to undo a democratically elected president from three years ago, and they're trying to interfere - yes, I said it - interfere in the next election, and I think America's smarter than that."

House investigators have no hearings scheduled Thursday, but Friday could be another key day in the probe, with both public and private testimony.

Marie Yovanovitch, the former ambassador to Ukraine who was recalled earlier this year by Trump, is scheduled to appear at an open hearing of the House Intelligence Committee.

She said in an Oct. 11 deposition that she was the target of a shadow campaign to orchestrate her removal that involved Trump's personal attorney Rudy Giuliani and Ukrainian officials suspected of fostering corruption, according to a transcript.

In her testimony, Yovanovitch said that she remained worried that she would be a target of retaliation by Trump, who referred to her in his July 25 phone call with Zelensky as “bad news” and someone who was “going to go through some things.”