A second whistleblower has come forward in the Ukraine scandal with first-hand knowledge of some of the allegations outlined in the original whistleblower complaint that's sparked an impeachment inquiry into President Donald Trump.

The New York Times on Friday reported that a second intelligence official with concerns about Trump's interactions with Ukraine was also considering filing a formal complaint and testifying to Congress.

Attorney Mark Zaid, who is representing both whistleblowers, told ABC News he doesn't know if the second whistleblower he represents is the person identified in the Times report.

Trump and his allies, including some Republicans in Congress, have dismissed the first complaint as hearsay given it relied on second-hand information. But the revelation that there's a second whistleblower with first-hand knowledge could further undermine the Trump administration's efforts to discredit the complaint.

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A second whistleblower has come forward in the escalating Ukraine scandal that has led to an impeachment inquiry into President Donald Trump, ABC News reported Sunday.

The whistleblower, an intelligence official, is represented by the same attorney who's representing the first whistleblower who filed a complaint in August related to Trump's dealings with Ukraine that was released in late September and has sent shockwaves through Washington.

The complaint centered on a July 25 phone call between Trump and Ukrainian President Volodymyr Zelensky, in which Trump urged Zelensky to investigate former Vice President and his son, Joe Biden.

Mark Zaid, the attorney, said the second whistleblower spoke to the intelligence community inspector general, Michael Atkinson, and has first-hand knowledge of some of the allegations outlined in the original complaint.

Trump and his allies, including some Republicans in Congress, have dismissed the first complaint as hearsay given it relied on second-hand information.

But the acting Director of National Intelligence Joseph Maguire recently told congressional lawmakers that the complaint was "in alignment" with a memo released by the White House on the call. And the revelation of a second whistleblower with first-hand knowledge could further undermine the Trump administration's efforts to discredit the complaint.

Read more: Newly revealed text messages show Trump diplomats' internal turmoil over his pressure on Ukraine

The New York Times on Friday reported a second intelligence official with concerns about Trump's interactions with Ukraine was also considering filing a formal complaint and testifying to Congress, but Zaid told ABC News he doesn't know if the second whistleblower he represents is the person identified in this report.

This news also came just several days after US House Intelligence, Oversight and Reform, and Foreign Affairs Committees released a pile of text messages between US diplomats — obtained as part of the impeachment inquiry — that point to a broad effort to urge Ukraine to investigate the Bidens. The messages included discussions of military aid and the possibility of a meeting between Trump and Zelensky, and questions on whether these things were conditioned on investigations in the former vice president and his son.

The whistleblower complaint that has spared the impeachment inquiry alleges Trump used the power of his office to "solicit interference from a foreign country" in the 2020 US election.

Trump ordered his administration to withhold a nearly $400 million military-aid package to Ukraine days before the phone call with Zelensky, and combined with the complaint, the White House memo on the call, and the text messages this has raised questions about the possibility of a quid pro quo among the president's critics. Trump has denied there was any quid pro quo linked to his efforts to pressure Ukraine to investigate Biden, a top political rival and leading contender for the 2020 Democratic nomination.