Zaid tells ABC News' Chief Anchor George Stephanopoulos that the second person - also described as an intelligence official - has first-hand knowledge of some of the allegations outlined in the original complaint and has been interviewed by the head of the intelligence community's internal watchdog office, Michael Atkinson. He said the second whistleblower has firsthand knowledge of the events in question due to their experience in the intelligence field.
Trump has denied any wrongdoing, calling the phone call "perfect".
This comes as Democrats have launched an impeachment inquiry based on a whistleblower complaint that accused Trump of "using the power of his office to solicit interference from a foreign country in the 2020 U.S. election".
"There's a lot of talk about Biden's son", Trump told Zelenskiy at one point, offering the assistance of his attorney general.
Democrats to subpoena White House for Ukraine documents
Among the documents being sought are any communications among administration officials involving Trump's phone call with Zelensky. Trump, who is seeking a second four-year term as president, has denied wrongdoing and has assailed the impeachment probe.
"Suppose he gets impeached, I think [Mike Pence] is dead to rights too because he was the VP", McKee said.
U.S. president Donald Trump's personal attorney Rudy Giuliani said in a TV show on Fox News that he had proof about former vice-president Joe Biden's alleged dealings in Romania. "I will put the integrity of my whole career in public service to this nation up against Trump's lack of integrity any day".
Perry also "played an active role in the Trump administration's efforts to shape decisions by the newly elected government of President Volodymyr Zelensky", and "pushed for Ukraine's state-owned natural gas company Naftogaz to expand its board to include Americans". Romney had said on Twitter that "By all appearances, the President's brazen and unprecedented appeal to China and to Ukraine to investigate Joe Biden is wrong and appalling".
Rep. Jim Himes of CT, appearing on CBS' "Face the Nation", predicted that more staff members in sensitive positions would either initiate whistleblower complaints or provide damaging information to the news media. Joe Biden is a leading candidate for the 2020 Democratic presidential nomination. He said the biggest problem is that the military aid to Ukraine yielded during Trump's phone call with Zelensky could be considered as quid quo pro, as Trump provided aid in return for dirt on Biden.
Democrats, meanwhile, suggested that others with crucial knowledge of events surrounding Trump's twin obsessions with the Bidens and the 2016 vote might now feel emboldened to come forward, whether out of self-preservation or a sense of moral outrage.
On Sunday morning, he sent out back-to-back tweets saying that "the great Scam is being revealed!" and the "Do Nothing Democrats are being exposed!" "And Republicans better get behind that".