The director of the US National Security Agency was fired on Thursday, according to Democratic lawmakers, as President Donald Trump extended his purge of America’s security establishment.

The dismissal came just hours after President Trump sacked a number of senior National Security Council officials following claims by a far-right activist of disloyalty to his “Make America Great Again” agenda.

Mark Warner, vice-chair of the Senate intelligence committee, condemned the dismissal of Timothy Haugh, the NSA director who also heads US Cyber Command, saying he had served “in uniform, with honour and distinction, for more than 30 years”.

The Washington Post first reported Haugh’s ouster. His civilian deputy at the NSA, Wendy Noble, was reassigned to another Pentagon position, the Post said.

The Pentagon and White House did not respond to a request for comment.

The NSA is the main US agency responsible for collecting signals intelligence and the NSC is the White House bureaucracy that advises the president on national security matters.

The NSC firings occurred after a meeting between Trump and Laura Loomer, a rightwing social media personality and conspiracy theorist, who presented him with research into certain staff members and urged him to sack them.

Their boss, the national security adviser Mike Waltz, was present at the Oval Office meeting alongside vice-president JD Vance and other senior officials, according to the New York Times, which was the first media outlet to report the encounter.

One person familiar with the development said at least three NSC officials had been fired, including Brian Walsh, who was responsible for intelligence issues, and Thomas Boodry, the legislative affairs director who previously worked for Waltz when he was a member of the US Congress.

The White House also fired David Feith, the senior director for technology. Feith is a China hawk who would have played an instrumental role in pushing security-related measures against Beijing, including export controls.

A second person said Waltz had been under increasing pressure from the Maga camp who viewed him as a neoconservative with very hawkish foreign policy views on countries from Iran to China. Another person said the oustings suggested Waltz himself was increasingly on thin ice since he was unable to protect his people.

A spokesperson for the NSC, Brian Hughes, refused to confirm or deny the firings, saying only that the NSC “doesn’t comment on personnel matters”.

When asked about the dismissals, Trump told reporters aboard Air Force One: “We’re always going to let go of people we don’t like or people that we don’t think can do the job or people that may have loyalties to someone else.”

He denied firing the officials at Loomer’s urging. “She makes recommendations of things and people, and sometimes I listen to those recommendations, like I do with everybody.”

Loomer has also taken aim at Alex Wong, the deputy national security adviser, and Ivan Kanapathy, the senior NSC director for Asia. Both are respected China hawks.

Loomer has called Wong, a Chinese-American foreign policy expert, the “Chinese national security adviser” in a social media post. The activist has targeted Kanapathy, a retired fighter pilot, because he worked for a consultancy that employs a few senior Democrats previously criticised by the Trump administration.

Waltz was under pressure before the meeting over revelations that he had created a chat group on Signal, a publicly available messaging app, to discuss details of a military strike on Houthi rebels in Yemen and had inadvertently invited a journalist, Atlantic editor Jeffrey Goldberg, to join.

The Pentagon’s watchdog, the Department of Defense Office of Inspector General, announced on Thursday that it had launched a probe into defence secretary Pete Hegseth’s use of Signal at the request of senators Roger Wicker and Jack Reed, the top Republican and Democrat, respectively, on the powerful Senate armed services committee.

“Per our long-standing policy, we don’t comment on ongoing investigations,” the Pentagon said in a statement.

Warner said it was “astonishing” that Trump would fire Haugh, the “non-partisan, experienced leader” of the NSA, “while still failing to hold any member of his team accountable for leaking classified information on a commercial messaging app”.