• Harvard University President Claudine Gay resigned amid new allegations of plagiarism.
• Gay is the second Ivy League leader to step down after controversy over congressional testimony about antisemitism on campus in the wake of the attack by Hamas on Israel.
• She was the first Black person and only the second woman to serve as Harvard's president, holding that post for just over six months.
• Rep. Elise Stefanik, a New York Republican, in a post on X wrote, "Two down," referring to Gay and the former president of the University of Pennsylvania, Liz Magill.

Harvard University President Claudine Gay resigned Tuesday amid new allegations of plagiarism, becoming the second Ivy League leader to step down after controversy over their congressional testimony last month about antisemitism on campus.

Gay, who was the first Black person and only the second woman to serve as Harvard's president, held that post for just over six months. Her tenure is the shortest in the university's history.

Alan Garber, Harvard's provost and chief academic officer, will serve as the university's interim president while the Harvard Corporation searches for a permanent replacement.

"It is with a heavy heart but a deep love for Harvard that I write to share that I will be stepping down as president," Gay said in a statement Tuesday.

"This is not a decision I came to easily. Indeed, it has been difficult beyond words because I have looked forward to working with so many of you to advance the commitment to academic excellence that has propelled this great university across centuries," she said.

"But, after consultation with members of the Corporation, it has become clear that it is in the best interests of Harvard for me to resign so that our community can navigate this moment of extraordinary challenge with a focus on the institution rather than any individual," Gay said.

On Monday, the Free Beacon news site reported that a new unsigned complaint filed with Harvard had six new allegations of plagiarism against Gay.

The Harvard Corporation several weeks ago said that an "independent review" of Gay's published academic work had found several instances where she failed to adequately cite a source, and that she was requesting changes to two articles to correct that failure. But additional claims of plagiarism followed that statement, up to and including Monday, even as Gay said she was standing by the "integrity of my scholarship."

A spokesman for Harvard, and Gay's office, did not immediately respond to CNBC's requests for comment.

Gay and then-University of Pennsylvania President Liz Magill were criticized for answers they gave to Rep. Elise Stefanik, R-N.Y., and others at a Dec. 5 House committee hearing on antisemitism on university campuses in the wake of the Oct. 7 attack on Israel by Palestinian militant group Hamas.

Stefanik asked Gay and Magill, as well as Massachusetts Institute of Technology President Sally Kornbluth, if "calling for the genocide of Jews" would violate their respective schools' codes of conduct.

Magill and Gay were blasted for not directly answering such questions, saying that whether there was a conduct code violation depended on the context of the antisemitic statement.

They both later issued statements that said they should have been clearer in condemning such speech.

Magill resigned on Dec. 10. Gay kept her job for several more weeks after the Harvard Corporation, which governs the university, gave her its backing.

Stefanik in a tweet on Tuesday responded to Gay's resignation by writing, "TWO DOWN."

"@Harvard knows that this long overdue forced resignation of the antisemitic plagiarist president is just the beginning of what will be the greatest scandal of any college or university in history," wrote Stefanik.

In a statement, the Harvard Corporation said it was accepting Gay's resignation "with sorrow."

"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," the statement 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. We condemn such attacks in the strongest possible terms."

Don't miss these stories from CNBC PRO:

• These stocks will be the biggest S&P 500 winners of 2024, according to analysts
• Here's where to invest $50,000 in the new year, according to the pros
• Could a bitcoin ETF approval be a sell-the-news event? Here's what to expect if it happens
• These stocks will be the biggest Dow winners of 2024, according to analysts
• Oprah's flip on weight loss drugs is a sign of what's to come for the 'Ozempic trade' in 2024