Intelligence Community inspector general Michael Atkinson on Thursday declined to provide lawmakers on the House Intelligence Committee with details of a controversial whistleblower complaint that allegedly involves a conversation between President Trump and an unknown foreign leader, according to Chairman Adam Schiff (D-Calif.).

"In the absence of that whistleblower law, there is no lawful mechanism for an intelligence community employer, detailee or contractor to raise a complaint about serious misconduct. The whole point of the whistleblower statute is not only to encourage those to report problems, abuses, violations of laws, but also to have a legal mechanism to do so and not to disclose classified information — because there's no other remedy. That whole purpose is being frustrated here because the director of national intelligence has made the unprecedented decision not to share the complaint with Congress."

— Adam Schiff

What we know: On Aug. 12, a whistleblower filed a complaint with Atkinson, who serves as the watchdog for the U.S. intelligence community, that he deemed was "credible and urgent within the definition of the law." The Washington Post reported Wednesday night that the complaint concerned a communication between Trump and a foreign leader in which the president made some kind of "promise."

Acting director of National Intelligence Joseph Maguire has refused to turn over the complaint to Congress, as is usually required by law. Schiff said Thursday that he does not know whether press reports about the nature of the Trump conversation are accurate, but that the Department of Justice was involved in the decision to withhold the complaint.

White House records show that Trump interacted with the following 5 foreign leaders in the 5 weeks preceding the complaint, though it's not clear if any of them are involved, according to the Post:

Russian President Vladimir Putin

North Korean dictator Kim Jong-un

Pakistan Prime Minister Imran Khan

Netherlands Prime Minister Mark Rutte

Qatar Emir Sheikh Tamim bin Hamad Al Thani

What's next: Schiff said he is consulting with the House general counsel to determine whether to take the Trump administration to court in order to obtain the complaint. Schiff also said he is considering using Congress' "power of the purse" to exert leverage over the DNI.

Maguire will testify in open session before the House Intelligence Committee next week under threat of subpoena.

What Trump is tweeting:

"Another Fake News story out there - It never ends! 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! 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!"

The bottom line: The lack of communication between Trump's top intelligence official and the Democratic-led House is the "latest in a series of fights over information" from the White House, per the New York Times. It could be the most significant one yet.