Laura Loomer, the far-right activist and promoter of conspiracy theories, met on Wednesday with President Trump in the Oval Office, where she pressed for him to fire National Security Council staff members whom she deemed disloyal to him, according to seven people with knowledge of the events.

Mr. Trump is likely to act on some of Ms. Loomer’s recommendations, two of the people said. Ms. Loomer walked into the White House with a sheaf of papers, which amounted to a mass of opposition research attacking the character and loyalty of numerous N.S.C. officials, two of the people said. She proceeded to excoriate them in front of their boss, the national security adviser Michael Waltz, who was also in the meeting.

Ms. Loomer’s rhetoric and actions have been so extreme that she has alienated even others on the far right. She has shared a conspiracy theory on social media calling the Sept. 11, 2001, terrorist attacks an “inside job.” During the 2024 campaign, Ms. Loomer said that “the White House will smell like curry” if Kamala Harris were elected, a jab at her Indian heritage. During the Republican primary campaign, in which she served as Mr. Trump’s online attack dog against Gov. Ron DeSantis of Florida, Ms. Loomer floated the baseless notion than Mr. DeSantis’s wife, Casey, had lied about having breast cancer.

But on Wednesday afternoon, she sat with the president in the Oval Office, plying him with claims about staff members whom she insisted he should dismiss. News of her attendance was first reported by the newsletter Status, but the details of what was discussed had not been revealed.

The meeting came after a recent string of social media attacks by Ms. Loomer on Trump administration officials, including Alex Wong, the deputy national security adviser. Mr. Wong’s boss, Mr. Waltz, has been under fire from detractors both inside and outside the administration for more than a week after the revelation that he created a group on Signal, a nonsecure commercial messaging app, to discuss sensitive details of a military strike in Yemen and inadvertently added a journalist to the chat.

Mr. Waltz was already on shaky footing before the incident and now may lose the ability to protect his staff from dismissals, with several senior staff members potentially on the chopping block. Mr. Trump has spoken somewhat sympathetically about Mr. Wong in some of his private conversations with advisers.

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