Following a closed-door briefing with the intelligence community’s inspector general on Thursday, members of Congress told reporters that they learned no substantive details about a whistleblower’s complaint that reportedly involves President Donald Trump making a “promise” to an unknown foreign leader—but were told that the complaint’s subject “relates to one of the most significant and important of the DNI’s responsibilities to the American people.”

Only minutes after that briefing’s conclusion, The New York Times reported that Michael Atkinson, the intelligence community’s inspector general, told members of the House Permanent Select Committee on Intelligence that the complaint related to “multiple acts,” far beyond the scope of a single alleged conversation with a foreign leader.

But specifics of the complaint—and even public confirmation that it concerns actions by the president—are still being withheld from Congress, committee members said.

Rep. Adam Schiff (D-CA) told reporters after the briefing that he believes the details of the complaint—which would normally be shared with Congress—are being suppressed, either by President Trump himself or someone “close” to him and “above the pay grade” of acting Director of National Intelligence Joseph Maguire.

“I don’t think this is a problem of the law,” Schiff, chair of the House Intelligence Committee, said. “The problem lies elsewhere. And we’re determined to do everything we can to determine what this urgent concern is, to make sure that the national security is protected and to make sure that this whistle-blower is protected.”

Fellow House Intelligence member Rep. Jackie Speier (D-CA) told reporters after the whistleblower briefing that “we’ve got a very grave situation on our hands. The standard that has to be met by the IG... urgent, is talking about fire, as he referred to it."

“This whistleblower has done everything according to the book,” Speier said. “And the potential for reprisals for this whistleblower are great”

The complaint in question, first filed with Atkinson’s office in mid-August and reported by the Washington Post, reportedly concerns a “promise” made while Trump was speaking with another world leader. In the five weeks preceding the complaint’s filing, Trump had conversations with at least five foreign leaders, including President Vladimir Putin of Russia, North Korean dictator Kim Jong Un, and Sheikh Tamim bin Hamad Al-Thani, the emir of Qatar.

Legally, such a complaint must involve mismanagement, waste, abuse, or a danger to intelligence operations or public safety, or relate to an intelligence activity that violates U.S. law.

—With additional reporting by Sam Brodey.