Mark Zaid, a lawyer for the original whistleblower in the case, said Sunday that his team now represented a second person who had come forward. According to the memorandum, Trump repeatedly asked Zelensky to "look into" the situation regarding a probe into former U.S. Vice President Joe Biden's son in Ukraine.
The telephone call and the whistleblower complaint prompted House of Representatives Speaker Nancy Pelosi to launch impeachment proceedings on September 24 against Trump, saying his actions jeopardized USA election integrity and threatened national security.
The initial whistleblower's complaint alleged the President abused his official powers "to solicit interference" from Ukraine in the upcoming 2020 election, and that the White House took steps to cover it up.
A Democrat on the House Intelligence Committee, Florida Representative Val Demings, said she believes the original whistle-blower is a "patriot" who stepped forward to report wrongdoing despite the potential career risk.
Jordan also touched on former U.S. Special Envoy to Ukraine Kurt Volker's testimony on the whistleblower complaint before the House Intelligence, Oversight and Foreign Affairs committees behind closed doors Thursday.
As Rudy Giuliani pushed Ukrainian officials last spring to investigate one of Donald Trump's main political rivals, a group of individuals with ties to the president and his personal lawyer were also active in the former Soviet republic.
Mr Trump railed against the "do-nothing" Democrats' impeachment yesterday on Twitter with a string of retweets from supporters, touting his high approval ratings among Republicans and reprising his criticism of Mr Romney.
But Perry told an evangelical Christian news outlet, CBN News, in an interview aired Friday that he had never heard anyone in the administration bring up Biden or Biden's son, who served on a board of a Ukraine natural gas business, in dealings with Ukrainian officials.
Senate Majority Leader Mitch McConnell accused Speaker of the House Nancy Pelosi of being "in the clutches of a left-wing mob" and was being forced to proceed with impeachment proceedings against President Trump.
She added Mr Trump's attempts to "solicit foreign interference jeopardized USA election integrity and threatened national security".
"The Democrats are lucky that they don't have any Mitt Romney types", Trump wrote, painting the 2012 GOP presidential nominee as a traitor to his party.
Democrats - derided in a Trump tweet Sunday as "DONOTHINGDEMOCRATS" - insist that they will continue pushing for action on key issues like health care and gun control even as the impeachment inquiry absorbs a huge amount of Washington's attention and energy.
"George, you really think he was serious about thinking that China's going to investigate the Biden family?".