Ukraine is at the center of a complaint made by a whistleblowing intelligence officer who filed the report after learning of a promise President Donald Trump made to a foreign leader, The Washington Post reported Thursday evening.
The newspaper cited two people familiar with the matter whom it did not name. The Trump administration has withheld the details of the report from Congress; though it was known that the complaint involved a foreign leader, the Post was the first to report the country involved.
NBC News has not confirmed that Ukraine is at the center of the issue. A request for comment from the White House was not immediately returned.
The newspaper first reported this week that the complaint was by an intelligence officer troubled by a promise Trump had made during communication and interaction with a foreign leader.
A former U.S. intelligence official familiar with the matter confirmed to NBC News Wednesday night that the whistleblower complaint involves a phone conversation that Trump had.
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Two and a half weeks before the whistleblower complaint was filed, Trump spoke with Ukraine's new president, Volodymyr Zelensky, the Post reported. House Democrats announced last week that they will investigate the role of Trump's personal lawyer, Rudy Giuliani, in what they characterized as efforts to influence the government of Ukraine to help the Trump re-election campaign.
The Post's editorial board on Sept. 5 had suggested that Trump was withholding military aid to Ukraine to pressure it to investigate Joe Biden and his son, Hunter Biden, who is on the board of a Ukrainian gas company.
In a combative interview with CNN on Thursday, Giuliani both denied and admitted to being in touch with Ukraine officials about the former vice president.
"No, actually I didn't. I asked Ukraine to investigate the allegations that there was interference in the election of 2016 by the Ukrainians for the benefit of Hillary Clinton," Giuliani said.
And minutes later, he appeared to contradict himself after anchor Chris Cuomo said "So you did ask Ukraine to look into Joe Biden."
"Of course I did," Giuliani said.
The New York Times reported Thursday that the details of the allegation remain opaque but involve at least one instance of Trump making an unspecified commitment to a foreign leader and include other actions, and that at least part of the allegation deals with Ukraine. It cited interviews and two people familiar with the complaint.
The acting director of national intelligence, Joseph Maguire, has been withholding the whistleblower complaint from House intelligence committees.
Maguire's decision infuriated House Intelligence Committee Chairman Adam Schiff, D-Calif., who has demanded Maguire's testimony and a copy of the complaint.
The inspector general for the intelligence community, an independent watchdog, deemed the complaint an "urgent concern" that he was required by law to turn over to the congressional intelligence committees.
But Maguire, after consulting with the Justice Department, overruled him, according to a series of letters between a DNI lawyer and Schiff that have been made public.
It is not clear from the Post's report and other reporting by NBC News what the alleged promise to a foreign leader entailed.
A whistleblower complaint by an intelligence official about a private presidential phone call would be an extraordinary development, likely without precedent in U.S. history.
Trump on Thursday disputed reports about the whistleblower complaint involving communication with a foreign leader, calling them "fake news." He said that when he speaks on the phone to foreign leaders there may be others from the U.S. listening in, and that he would never say anything "inappropriate" to a foreign leader on such a call.
"Virtually anytime I speak on the phone to a foreign leader, I understand that there may be many people listening from various U.S. agencies, not to mention those from the other country itself. No problem!" Trump tweeted.
"Knowing all of this, is anybody dumb enough to believe that I would say something inappropriate with a foreign leader while on such a potentially 'heavily populated' call. I would only do what is right anyway, and only do good for the USA!" Trump continued.
The inspector general, Michael Atkinson, was in a closed-door briefing with members of the House Intelligence Committee for several hours Thursday, but a congressional source tells NBC News that Atkinson declined to reveal to lawmakers the substance of the whistleblower complaint.
Schiff said Thursday night on MSNBC after the Post published its report that "we haven't received the complaint" and did not confirm that it involved Ukraine.
He said that the dispute between the DNI and his committee is not one over policy, but over information that Congress has a right to know.
"This involves an allegation of serious wrongdoing, something that the inspector general felt needed to be presented to Congress," Schiff told Rachel Maddow Thursday night.
"It is unprecedented for a director to withhold that information from Congress," Schiff said. If whistleblowers file complaints under the law and the complaint is withheld from Congress, he said, it could have a chilling effect on the system and that important information about wrongdoing could go unreported.
In the CNN interview, Giuliani agreed that whistleblowers deserve protection but said that "some whistleblowers are liars."
"This whistleblower could be telling the truth, or this whistleblower could be a Democrat holdover who is trying to destroy Donald Trump," Giuliani said.