Attorney General Jeff Sessions on Tuesday said he thinks American universities have transformed into shelters “for the fragile ego” and equated student protesters to members of the Ku Klux Klan.

“The American university was once the center of academic freedom—a place of robust debate, a forum for the competition of ideas,” he said during remarks on free speech at Georgetown University’s law school. “But it is transforming into an echo chamber of political correctness and homogenous thought, a shelter for fragile egos.”

He cited instances on college campuses that he claimed were either a violation of students’ freedom of speech — like students who were arrested in Michigan for passing out copies of the Constitution — or a university’s attempt to shut down diversity of thought.

Specifically he spoke about a “frightening” incident at Middlebury College in Vermont, in which a guest speaker was invited to the school to debate with a professor. Protesters shut down the discussion by shouting, he said.

“When the debaters attempted to move to a private broadcasting location, the protestors—many in masks, a common tactic also used by the detestable Ku Klux Klan — pulled fire alarms, surrounded the speakers, and began physically assaulting them,” he said. “In short, Middlebury students engaged in a violent riot to ensure that neither they nor their fellow students would hear speech they may have disagreed with.”

The guest speaker who was invited to the private liberal arts school for a debate was Charles Murray, the controversial co-author of “The Bell Curve,” which argues that there may be intellectual differences between races.

The protest turned violent at one point after students shut down the debate. Many of the protesters were wearing masks and hoods, according to the Atlantic and The New York Times.

Ahead of Sessions’ appearance at Georgetown, at least 130 students were uninvited to the event, according to a press release from members of the Georgetown Law American Constitution Society. While the event was meant to be limited to small group of students, some members claim it was the students who discussed protesting the speech online who were uninvited.

A protest was held outside while Sessions spoke Tuesday.