WASHINGTON — The House Intelligence Committee on Monday unexpectedly added to its roster of public impeachment witnesses, announcing testimony later this week from a United States Embassy official in Kyiv who overheard President Trump ask a top American diplomat in July if Ukraine would move forward with investigations he sought.
The official, David Holmes, testified before investigators privately on Friday. Now, he will sit at the witness table beside Fiona Hill, the former senior director for Russia and Europe at the National Security Council, when the committee convenes its final hearing of a jam-packed week on Thursday.
Behind closed doors, Mr. Holmes described being at a restaurant in Kyiv, Ukraine’s capital, over the summer when Gordon D. Sondland, the American ambassador to the European Union, called Mr. Trump on his cellphone. Speaking loudly enough for Mr. Holmes to hear, Mr. Trump asked Mr. Sondland if Ukraine’s president had agreed to conduct an investigation into one of his leading political rivals, Mr. Holmes said. And in colorful terms, the ambassador, fresh off meetings with top Ukrainian officials, told Mr. Trump that he had.
The addition to the week’s already busy public hearing schedule came as Speaker Nancy Pelosi defended the impeachment inquiry, arguing that lawmakers have no choice but to dig into what she called clear evidence of wrongdoing by Mr. Trump.
“The facts are uncontested: that the president abused his power for his own personal, political benefit, at the expense of our national security interests,” Ms. Pelosi wrote in a letter to Democratic colleagues.
The House Intelligence Committee will now take testimony from nine witnesses this week in the impeachment inquiry, in public hearings intended to prove that Mr. Trump pressured Ukraine to publicly commit to investigations to discredit his political rivals.
House Republicans, who will have their first chance to question witnesses they believe will undercut the allegations, have also requested that a Republican senator who has repeatedly found himself drawn into the impeachment inquiry tell them what he knows about Mr. Trump’s dealings with Ukraine.
The top Republicans on the Oversight and Intelligence Committees wrote to Senator Ron Johnson, Republican of Wisconsin, that they were “reluctantly” requesting “any firsthand information you have about President Trump’s actions toward Ukraine,” according to their letter released Monday.
As Mr. Johnson appeared to mull their request, Mr. Trump wrote on Twitter that he would “strongly consider” testifying in the impeachment inquiry, after Ms. Pelosi raised the idea during a weekend television interview.
“Even though I did nothing wrong, and don’t like giving credibility to this No Due Process Hoax, I like the idea & will, in order to get Congress focused again, strongly consider it!” Mr. Trump wrote.
Hours later, in her letter to Democrats, Ms. Pelosi rebutted what has emerged as a leading argument among Republicans against the inquiry: that the upcoming presidential election, not a vote on articles of impeachment, should decide Mr. Trump’s political fate.
“That dangerous position only adds to the urgency of our action, because the president is jeopardizing the integrity of the 2020 elections,” Ms. Pelosi said.
House Republicans are hoping Mr. Johnson, a member of the bipartisan Senate Ukraine Caucus, can help shed light on why Mr. Trump withheld a package of nearly $400 million in military assistance for Ukraine. Mr. Johnson traveled to Ukraine as part of a delegation attending President Volodymyr Zelensky’s inauguration this year, and joined phone calls between Mr. Trump and the American ambassador to the European Union, Gordon D. Sondland, who is a witness in the inquiry.
Typically a staunch defender of the president, Mr. Johnson has said that he confronted Mr. Trump in a phone call in late August about allegations that the president was engaging in a quid pro quo with Ukraine tying the security aid for the country to a public commitment for investigations that Mr. Trump wanted. The president, Mr. Johnson has said, flatly denied it.
But the senator has also revealed information that could be damaging to Mr. Trump: that Mr. Sondland told him that the aid to Ukraine was, in fact, tied to Mr. Trump’s request to have Kyiv investigate Democrats. He told reporters at an event in Wisconsin that he had tried to get permission from Mr. Trump to tell Ukraine’s president that American aid was on its way in the wake of those allegations, but the president refused.
Republicans have argued that the fact that the military funding was ultimately delivered to Ukraine in September, without any announcement of investigations by the country, proves that there was never any effort to tie the two issues together.
But Ms. Pelosi noted in her letter that the money “was only released after the whistle-blower exposed the truth of the president’s extortion and bribery, and the House launched a formal investigation.”
Mr. Johnson was one of several senators in both parties who were deeply concerned about the hold that had been placed on the military aid for Ukraine, which had been allocated by Congress to help the former Soviet republic defend itself from attacks by Russia, and who pressed privately and publicly for it to be released.
Mr. Johnson said on “Meet the Press” on Sunday that he would not be called to testify before the House, “because certainly Adam Schiff wouldn’t want to be called by the Senate.” But he added, “I’ll supply my telling of events.”