Washington — The attorneys representing the whistleblower who filed a complaint about President Trump's dealings with Ukraine said they are representing "multiple whistleblowers" in connection to the case, including one with "first hand knowledge" of events.

"I can confirm that my firm and my team represent multiple whistleblowers in connection to the underlying August 12, 2019, disclosure to the Intelligence Community Inspector General," attorney Andrew Bakaj tweeted Sunday. "No further comment at this time."

Mark Zaid, another member of the first whistleblower's legal team, also said the team is representing a second official with first-hand knowledge of events, as first reported by ABC News. The original whistleblower had not heard or seen a transcript of the phone call between Mr. Trump and Ukrainian President Volodymyr Zelensky at the center of the August 12 complaint.

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"I can confirm this report of a second #whistleblower being represented by our legal team," Zaid tweeted. "They also made a protected disclosure under the law and cannot be retaliated against. This WBer has first hand knowledge."

On Friday, the New York Times reported a second official was considering coming forward. It's unclear whether that official is the same person Zaid was referencing, or how many others may have formally filed complaints.

The first whistleblower's complaint raised concerns about a phone call between Mr. Trump and Zelensky on July 25, in which the president urged the Ukrainian leader to open investigations into the origins of the counterintelligence probe that became the Mueller investigation, as well as a Ukrainian energy company that hired Hunter Biden, the former vice president's son.

President Trump meets with Ukrainian President Volodymyr Zelensky during the United Nations General Assembly, Wednesday, September 25, 2019, in New York. AP

The whistleblower first consulted with staff from the House Intelligence Committee, who urged the person to obtain counsel and approach the intelligence community inspector general. The individual filed a nine-page complaint on August 12, saying he or she had learned from "multiple U.S. government officials that the President of the United States is using the power of his office to solicit interference from a foreign country in the 2020 U.S. election."

The inspector general, Michael Atkinson, deemed the complaint credible and said it constituted an "urgent concern," forwarding the complaint and his assessment to Acting Director of National Intelligence Joseph Maguire on August 26. After consulting with the White House counsel and Department of Justice, Maguire decided against providing it to Congress.

During congressional testimony, Maguire strongly defended his decision, saying he acted in good faith and was simply delaying transferring the complaint to Congress because of its "unprecedented" nature.

Atkinson would write to House Intelligence Committee Chairman Adam Schiff to inform him of Maguire's decision, and Schiff issued a subpoena for the complaint on September 13, revealing its existence publicly for the first time.

Olivia Gazis contributed reporting.