Donald Trump has rubbished a report alleging he made a promise to a foreign leader, something that sparked a whistleblower’s formal complaint.
The Washington Post said the intelligence official found the comment “so troubling” they went to the department’s inspector general.
In a tweet, Mr Trump dismissed the claims as “fake news”.
Democrats are trying to get the complaint turned over to Congress, with the details still unknown.
It is not yet known who made the complaint, which foreign leader Mr Trump was speaking to, what “promise” was made and whether Mr Trump took any action as a result.
The complaint was determined to be “credible” by Intelligence Community Inspector General Michael Atkinson, who labelled it a matter of “urgent concern”, requiring congressional oversight committees to be alerted, the Washington Post reported.
It was filed on 12 August, while Mr Trump was at his golf resort in New Jersey, according to the Post, which noted five foreign leaders with whom Mr Trump had interactions in the preceding five weeks.
During that time he phoned Russia’s Vladimir Putin, received at least two letters from North Korean dictator Kim Jong Un, and met at the White House with the leaders of Pakistan, the Netherlands and Qatar.
In his tweet Mr Trump wrote “is anybody dumb enough to believe that I would say something inappropriate with a foreign leader”.
Acting Director of National Intelligence Joseph Maguire has so far refused to share any details of the complaint with lawmakers, leading to an outcry among Democrats.
House Intelligence Chairman Adam Schiff, a Democratic California Congressman, praised the whistleblower for coming forward after a closed hearing with Mr Atkinson on Thursday.
Trump vs spies
Analysis by Tara McKelvey, White House reporter
Many of those who work in the US intelligence services don’t trust Trump. They don’t think that he can keep a secret (he apparently revealed classified information to Russians in the Oval Office), and they don’t like the way he talks about them (in a tweet about a news leak, he compared them to Nazis).
The controversy over the president’s “promise” to a foreign leader during a phone call – and a whistleblower complaint about the matter – is a reminder of the acrimonious relationship between the president and those who work in the intelligence services.
Yet like much of what happens in the world of intelligence, the matter is shrouded in mystery. It’s still unclear whom the president spoke to, for example, or what he said. In this case, though, some of these questions will be addressed during a House intelligence committee scheduled for next week, and more information may be available to the public.
As Trump himself would say: stay tuned.