A major University of Pennsylvania donor has withdrawn a $100m (£79.3m) grant after a controversial appearance in congress by the school's president.

President Elizabeth Magill met representatives alongside Harvard President Claudine Gay and Sally Kornbluth of MIT on Tuesday.

But they caused anger after avoiding questions on how students calling for the genocide of Jews would be punished.

The donor, Ross Stevens, said he was appalled" by her stance.

US college campuses have seen angry protests since the war between Israel and Hamas erupted two months ago.

In an email, seen by the BBC, Mr. Stevens said: I have clear grounds to rescind Penn's $100 million of Stone Ridge shares due to the conduct of President Magill.

The founder and CEO of Stone Ridge Asset Management, Mr. Stevens told the university that its permissive approach to those calling for violence against Jewish people "would violate any policies or rules that prohibit harassment and discrimination based on religion, including those of Stone Ridge.

Penn is one of the oldest universities in the US and a part of the elite Ivy League group, which also has Harvard, Colombia and Yale as members.

The university in Philadelphia is also home to one of the world's most prestigious business schools, Wharton, which counts former US President Donald Trump, Tesla and SpaceX billionaire Elon Musk, and many other powerful names in business and finance among its graduates.

The donation, in the form of limited partnership units in Stone Ridge, was gifted by Mr Stevens in 2017 to help Wharton create a finance innovation centre.

There has been widespread backlash against the responses of the university leaders during their House of Representatives testimony, specifically regarding the question from Rep Elise Stefanik.

Does calling for the genocide of Jews violate [your university's] code of conduct or rules regarding bullying and harassment? Yes or no? the New York congresswoman asked.

The three university presidents did not reply yes or no, but said - in varying ways - that it depended on the context. New York Senator Kirsten Gillibrand, a Democrat, called their statements abhorrent.

Ms Magill in particular has faced mounting scrutiny as to whether she can continue in her position.

She released a video on the university's website on Thursday apologising for her response during the hearing, saying that she was focused on the "university's long-standing policies - aligned with the US Constitution - which say that speech alone is not punishable.

She added she should have been focused on the "irrefutable fact that a call for genocide of Jewish people is a call for some of the most terrible violence human beings can perpetrate, adding that it is evil, plain and simple.

While her apology on Wednesday was welcomed by some, Mr. Stevens' letter appeared to call for her resignation.

He said Stone Ridge would welcome the opportunity review its decision if, and when, there is a new University President in place.

CNN reported on Thursday evening that Scott Bok, the chair of Penn's Board of Trustees, would speak to Ms Magill about resigning in the coming days.

The House Committee on Education & the Workforce announced on Thursday that they will formally investigate Harvard, the University of Pennsylvania and the Massachusetts Institute of Technology over rampant anti-Semitism.

Committee members have deep concerns with their leadership and their failure to take steps to provide Jewish students the safe learning environment they are due under law, the committee's chairwoman Virginia Foxx said in a statement.

Islamophobic attacks have also been on the rise on university campuses.

The Department of Education has launched an investigation into multiple schools over alleged incidents of antisemitism and Islamophobia.

UPenn President Liz Magill's testimony on antisemitism prompted university donor Ross Stevens of Stone Ridge Asset Management to pull his $100 million gift to the school.