Tulsi Gabbard is leaving her post as US director of national intelligence following a tumultuous stint in which she was largely sidelined as Donald Trump launched attacks on Venezuela and Iran.

In a letter to the US president, she said she would resign and leave her post on 30 June. “While we have made significant progress … I recognize there is still important work to be done,” she wrote.

The White House forced Gabbard to resign, the Reuters news agency reported, citing a source familiar with the issue. Fox News was first to report Gabbard’s exit, citing her husband’s cancer diagnosis.

Trump was asking cabinet members last month whether he should replace Gabbard, according to two people briefed on the discussions.

“Unfortunately, after having done a great job, Tulsi Gabbard will be leaving the Administration on June 30th​,” he wrote in a statement on his Truth Social platform on Friday.

​Gabbard “has done an incredible job, and we will miss her​”, the president said, adding that Aaron Lukas,​ principal deputy director of national intelligence, would serve as ​acting ​director of ​national ​intelligence.

Gabbard already seemed marginalized last June, when Trump endorsed Israel’s decision to attack Iran before the US joined the war by ordering the bombing of the Islamic regime’s nuclear facilities.

The decision was a public repudiation of Gabbard’s earlier testimony on Capitol Hill that Iran was not building a nuclear weapon. Trump seemed to add insult to injury by declaring he did not care what she said, and dismissing her assessment as “wrong”.

Within weeks, Gabbard made a public effort to get back into the president’s good graces by calling for Barack Obama and several top national security officials in his administration to be prosecuted, alleging that they had conducted a “treasonous conspiracy” to falsely depict Russia as interfering in the 2016 election on Trump’s side.

Obama denied the allegations, which seemed designed to satisfy Trump’s “retribution” agenda against his political opponents.

This year, she provoked outrage among Democrats by turning up at the scene of an FBI raid to seize ballots from the 2020 presidential election, a setting far outside her predominantly foreign intelligence brief, but another sign that her priority was keeping on the good side of Trump.

By contrast, she was excluded from the decision-making surrounding the seizure of Venezuela’s president, Nicolás Maduro, in January, and likewise absent from key decisions and public statements concerning February’s decision to renew military strikes on Iran.

Gabbard’s apparent exclusion from key national security policy decisions vindicated those who doubted her qualifications for a post that gave her oversight of 18 intelligence agencies.

Her nomination following Trump’s November 2024 election victory was criticized by those who pointed to her repeating of Kremlin talking points over Russia’s war with Ukraine, and a meeting with the former Syrian dictator Bashar al-Assad in 2017, in which she told him that Syria was “not an enemy of the United States”.

Hillary Clinton had previously suggested that Gabbard, a former Democrat who left the party in 2022, was being “groomed” by Russia.

Democratic senator Mark Warner, the vice-chair of the Senate’s select committee on intelligence, said his thoughts were with Gabbard and her family but said he hoped her successor would help ensure that the “office remain grounded in facts, independence, and the rule of law”.

“The next DNI must be committed to restoring trust in the office, protecting the integrity of our intelligence, and ensuring our nation’s intelligence professionals can speak truth to power, without fear or interference,” he said.

Democratic senator Adam Schiff also wished Gabbard’s husband a swift recovery, before arguing that the departing intelligence director’s only advantageous contribution to US national security was her resignation. “She politicized intelligence. She dismantled critical agencies keeping Americans safe. She weaponized the [Intelligence Community] to pursue baseless election fraud claims. And more,” he wrote in a post on X.

He added: “We must ensure that her tenure – marked by a devotion to the person of the president and not to the security of the country – represents a terrible exception at DNI and not the new normal.”

Gabbard becomes the fourth woman to depart Trump’s cabinet in just over two months, following the ousting in March of Kristi Noem, the former homeland security secretary; Pam Bondi, who was fired as attorney general in April; and labor secretary Lori Chavez-DeRemer, who resigned in April after a series of misconduct allegations.

In a statement, the office of the director of national intelligence (ODNI) credited Gabbard with “a transformational effort to reshape the Intelligence Community in ways no predecessor had attempted”.

“It has been a bad 15 months for the ‘deep state’ with Tulsi Gabbard in charge,” said the ODNI spokesperson Olivia Coleman.

Among the supposed achievements trumpeted was the revoking of security passes of what Coleman called “Deep-State bad actors”, but who others said had been loyal career intelligence officers, as well as the release of previously classified files on the John F Kennedy, Robert F Kennedy and Martin Luther King assassinations.