Although the official details of the complaint have not been provided to members of Congress, Atkinson told the panel during the briefing that it raised concerns about multiple actions but would not say if those instances involved Trump, according to sources familiar with the briefing.
Trump on Sunday said that he did indeed discuss Biden with Ukraine's president - at a time when the country was awaiting the aid package from the United States - but he denied doing anything improper.
The president has sincedenied the report. "If you don't talk about corruption, why would you give money to a country that you think is, is corrupt?"
On Monday, The Washington Post first reported that the President had directed his acting chief of staff Mick Mulvaney to freeze almost $400 million of USA military and security aid to Ukraine in the days before he spoke with Zelensky. "Fortunately it finally happened, and I'm glad about that", McConnell said.
Trump and his personal lawyer, Rudy Giuliani, have spun the event as a major scandal, even though no evidence has emerged that Joe Biden attempted to help his son by pressing for Shokin's dismissal. McGuire will testify publicly Thursday morning before the House.
Accordingly, the Democrat-led Committee voted along party lines to broaden the impeachment probe and lay out the groundwork for a subsequent investigation.
"You don't ask a foreign government to interfere in our election", Pelosi said.
He said Republicans should tell the White House to release transcripts of Trump's conversation with the Ukraine president and identify who in the White House sought to delay the money to Ukraine.
But most congressional Republicans have either defended the president or remained silent.
While Trump remains defiant, asserting he did nothing wrong, Democrats have continued to ramp up calls for action.
There has been no official confirmation from Ms Pelosi, who as House Speaker is the most senior Democrat.
McConnell said the appropriate venue for the Senate to review the allegations was through the Senate Intelligence Committee.
That view may be pushing House leaders toward a tipping point for launching removal proceedings, along with their Democratic Senate colleagues.
But by the time the Obama administration joined with other Western nations to force Shokin's removal, the Burisma investigation had been long dormant, Shokin's former deputy Vitaliy Kasko said in an interview with Bloomberg News earlier this year.
A growing number of House Democrats, including civil rights icon John Lewis and seven freshmen, are throwing their support behind an impeachment inquiry. "I would never have been able to predict that Donald Trump would have picked me out as the tip of the spear against the one person they believe can beat them".
Senate Majority Leader Mitch McConnell on Tuesday would not speculate about how the Senate might handle articles of impeachment against President Donald Trump. "I want to make sure the wall gets funded, and I've talked to [the Department of Defense], and they're convinced we will get our funding for the project".
Moments before Pelosi spoke, Trump tweeted that he had authorized the release on Wednesday of a transcript of the call.
"I may do it because it was a very innocent call on both his part and mine", he said Monday of releasing the transcript of the call with Zelensky.
The Biden camp has argued that claims of wrongdoing are unfounded and have been debunked.
The president and his personal attorney, Rudy Giuliani, have accused Biden of acting inappropriately by pushing Ukraine to oust then-prosecutor general Viktor Shokin, who was considered by the USA government and European leaders to be corrupt. He called for the ouster of the top Ukrainian prosecutor, Viktor Shokin, for what was widely seen as his failure to investigate corruption. He is also scheduled to address the press at the close of the U.N. General Assembly.