WASHINGTON — The internal watchdog for American spy agencies declined repeatedly in a briefing on Thursday to disclose to lawmakers the content of a potentially explosive whistle-blower complaint that is said to involve a discussion between President Trump and a foreign leader, according to two people familiar with the briefing.
During a private session on Capitol Hill, Michael Atkinson, the inspector general of the intelligence community, told lawmakers he was unable to confirm or deny anything about the substance of the complaint, including whether it involved the president, according to the people, who spoke on condition of anonymity to describe the closed-door conversation. The meeting was still underway.
The complaint, which prompted a standoff between Congress and Mr. Trump’s top intelligence official, involves a commitment that Mr. Trump made in a communication with another world leader, according to a person familiar with the complaint. The Washington Post first reported the nature of the discussion. The acting director of national intelligence, Joseph Maguire, has refused to give the complaint to Congress, as is generally required by law, the latest in a series of fights over information between the Democratic-led House and the White House.
Few details of the whistle-blower complaint are known, including the identity of the world leader. And it is not obvious how a communication between Mr. Trump and a foreign leader could meet the legal standards for a whistle-blower complaint that the inspector general would deem an “urgent concern.”
Under the law, the complaint has to concern the existence of an intelligence activity that violates the law, rules or regulations, or otherwise amounts to mismanagement, waste, abuse, or a danger to public safety. But a conversation between two foreign leaders is not itself an intelligence activity.
And while Mr. Trump may have discussed intelligence activities with the foreign leader, he enjoys broad power as president to declassify intelligence secrets, order the intelligence community to act and otherwise direct the conduct of foreign policy as he sees fit, legal experts said.
Mr. Trump regularly speaks with foreign leaders and often takes a freewheeling approach. Some current and former officials said that what an intelligence official took to be a troubling commitment could have been an innocuous comment. But there has long been concern among some in the intelligence agencies that the information they share with the president is being politicized.
Andrew P. Bakaj, a former C.I.A. and Pentagon official whose legal practice specializes in whistle-blower and security clearance issues, confirmed that he is representing the official who filed the complaint. Mr. Bakaj declined to identify his client or to comment.
Mr. Trump denied wrongdoing on Thursday, explaining that he would not “say something inappropriate” on calls where aides and intelligence officials from both sides routinely listen in.
But whatever Mr. Trump said was startling enough to prompt the intelligence official to file a formal whistle-blower complaint on Aug. 12 to the inspector general for the intelligence agencies. Such a complaint is lodged through a formal process intended to protect the whistle-blower from retaliation.
Representative Adam B. Schiff, Democrat of California and the chairman of the House Intelligence Committee, has been locked in the standoff with Mr. Maguire over the complaint for nearly a week. He said Mr. Maguire told him that he had been instructed not to give the complaint to Congress, and that the complaint addressed privileged information — meaning the president or people close to him were involved.
Mr. Schiff said none of the previous directors of national intelligence, a position created in 2004, had ever refused to provide a whistle-blower complaint to Congress. The House Intelligence Committee issued a subpoena last week to compel Mr. Maguire to appear before the panel. He briefly refused but relented on Wednesday and is now scheduled to appear before the committee in an open hearing next week.
Senator Mark Warner of Virginia, the top Democrat on the Senate intelligence panel, said on Thursday that he and the committee’s Republican chairman, Senator Richard Burr of North Carolina, also expected both the inspector general and acting director to brief them early next week and “clear this issue up.”
Mr. Maguire and Mr. Atkinson are at odds over how the complaint should be handled. Mr. Atkinson has indicated the matter should be investigated, and alerted the House and Senate Intelligence committees, while Mr. Maguire, the acting director of national intelligence, says the complaint does not fall within the agencies’ purview because it does not involve a member of the intelligence community — a network of 17 agencies that does not include the White House.
The inspector general of the intelligence community “determined that this complaint is both credible and urgent, and that it should be transmitted to Congress under the clear letter of the law,” Mr. Schiff, Democrat of California, said in a statement on Wednesday evening.
Mr. Maguire was named the acting director in August, after the president had announced that the previous director of national intelligence, Dan Coats, would be stepping down. Mr. Trump had planned to nominate Representative John Ratcliffe, Republican of Texas, a Trump loyalist without an extensive background in intelligence. But the president dropped the plan after lawmakers from both parties raised concerns about Mr. Ratcliffe’s qualifications and possible exaggerations on his resume.
The reports about the whistle-blower complaint touched off speculation about what Mr. Trump said and to whom.
In the weeks before the complaint was filed, Mr. Trump spoke with President Vladimir V. Putin of Russia, Prime Minister Imran Khan of Pakistan and the prime minister of the Netherlands, Mark Rutte.
And current and former intelligence officials have expressed surprise that during his first few months as president, Mr. Trump shared classified information provided by an ally, Israel, with the Russian foreign minister.
Such disclosures are not illegal, but Mr. Trump flouted intelligence-sharing decorum by sharing an ally’s intelligence without express permission.
Charlie Savage contributed reporting.