Harvard University's president has resigned after facing allegations of plagiarism and criticism over her comments about antisemitism on campus.
Claudine Gay had faced mounting pressure to step down in recent weeks.
In a letter announcing her resignation, she said it was in the "best interests" of the university for her to go.
"It has been distressing to have doubt cast on my commitments to confronting hate and to upholding scholarly rigour," she said.
"This is not a decision I came to easily. Indeed, it has been difficult beyond words," Dr Gay wrote, adding that her resignation would allow Harvard to "focus on the institution rather than any individual".
She said she had been subjected to personal threats and "racial animus".
The 53-year-old served as president for six months and was the first black person, and the second woman, to be appointed to lead the Ivy League university. Her tenure was the shortest in its 388-year history.
Harvard is one of several universities in the US accused of failing to protect its Jewish students following the outbreak of the Israel-Hamas war in October. Jewish groups have reported an alarming rise in antisemitic incidents in the US since the conflict began.
During a tense congressional hearing last month, Dr Gay said calls for the killing of Jews were abhorrent. She added, however, that it would depend on the context whether such comments would constitute a violation of Harvard's code of conduct regarding bullying and harassment.
That comment prompted a widespread backlash and she later apologised in an interview with the university's student newspaper. "When words amplify distress and pain, I don't know how you could feel anything but regret," Dr Gay said.
Dozens of politicians and some high-profile alumni called for her to step down over the comments.
But nearly 700 staff members rallied behind her in a letter and the university said she would keep her job despite the controversy.
But since then US media outlets have unearthed several instances of alleged plagiarism in her academic record. Harvard's board investigated the allegations last month, and found two published papers that required additional citation.
The board, however, said that she did not violate standards for research misconduct.
More claims that Dr Gay had failed to properly cite academic sources emerged just hours before she resigned on Tuesday and were published anonymously in the conservative Washington Free Beacon newspaper.
The university's 11-member governing body, the Harvard Corporation, said in a statement that Dr Gay would resume her faculty position after resigning.
"While President Gay has acknowledged missteps and has taken responsibility for them, it is also true that she has shown remarkable resilience in the face of deeply personal and sustained attacks," it said.
"While some of this has played out in the public domain, much of it has taken the form of repugnant and in some cases racist vitriol directed at her through disgraceful emails and phone calls," the corporation added. "We condemn such attacks in the strongest possible terms."
University provost and chief academic officer, Alan Garber, will step in as interim president until a new one can be appointed, the Harvard Corporation said.
Dr Gay is the second university official to resign following the 5 December congressional hearing.
Former University of Pennsylvania president Elizabeth Magill resigned just days later after an angry backlash. A donor also withdrew $100m (£80m) in protest over her comments.
Massachusetts Institute of Technology (MIT) President Sally Kornbluth also testified at the hearing, and critics are now redoubling their calls for her to stand aside also.
Dr Gay's resignation, and the controversy surrounding her in recent weeks, has proved to be a highly charged issue and there was immediate political reaction on Tuesday.
Congressman Byron Donalds, a Florida Republican, posted on X, formerly Twitter, "two down, one to go" in a reference to the three college presidents who testified on Capitol Hill.
"Her answers were absolutely pathetic and devoid of the moral leadership and academic integrity required of the president of Harvard," Republican congresswoman Elise Stefanik said.
The Harvard Jewish Alumni Alliance welcomed her resignation, saying that as president, Dr Gay "tacitly encouraged those who sought to spread hate at Harvard, where many Jews no longer feel safe to study, identify and fully participate in the Harvard community".
Civil rights leader Al Sharpton, meanwhile, condemned the resignation and called it "an assault on the health, strength, and future of diversity, equity, and inclusion".
He announced plans to hold a protest on Thursday outside the New York office of Bill Ackman, a hedge fund manager and Harvard graduate who has led calls for Dr Gay to resign.
The Republican-led congressional committee that launched the probe into Harvard and other universities said its investigation would continue.
"There has been a hostile takeover of postsecondary education by political activists, woke faculty and partisan administrators," said North Carolina congresswoman Virginia Foxx, chairwoman of the committee.
"The problems at Harvard are much larger than one leader, and the committee's oversight will continue."
BBC