U.S. Secretary of Education Betsy DeVos was greeted by rounds of boos on Wednesday as students turned their backs to her during a graduation ceremony where she was the keynote speaker.

DeVos was selected to speak at Bethune-Cookman University in Daytona Beach, Florida, a historically black university, despite strong opposition by many students and community members to her presence.

“I am honored to become a Wildcat,” DeVos began her speech, after receiving an honorary doctorate, raising her voice as a chorus of boos attempted to drown her out.

#bethunecookmanuniversity graduates turn there backs as Besty De Vos speaks. Let's save our #HBCU #notmypresident #betsydevos is not for #ourchildrenmatter A post shared by Allie_Pinkliproject (@allie_pinkliproject) on May 10, 2017 at 10:14am PDT

“If this behavior continues your degrees will be mailed to you,” Bethune-Cookman President Edison Jackson told the crowd as the boos continued. “Choose which way you want to go.”

DeVos said she welcomed the opportunity to speak with students, including those who disagree with her.

“I want to reaffirm this administration’s commitment to and support for HBCUs and the students they serve,” she said. “Please know this: We support you and we will continue to support you.”

A large number of grads have their backs to DeVos now as she speaks. It's a little hard to hear her words. pic.twitter.com/yVXsqLVJQv — Molly Hensley-Clancy (@mollyhc) May 10, 2017

Students also shouted in opposition when Jackson acknowledged White House communications official Omarosa Manigault, who was sitting in the audience.

“You don’t know her, and nor do you know her story,” Jackson admonished the crowd, sparking more boos.

DeVos’ speech ignited immediate controversy when it was announced earlier this month, and students criticized the school for selecting her after she downplayed the role of racism in the creation of historically black colleges and universities.

Protesters on Tuesday delivered petitions to the school’s leaders, calling on them to cancel DeVos’ speech due to her ignorance of HBCUs and lack of support for student loan borrowers. Organizers said they had collected 50,000 signatures.

DeVos praised HBCUs as “real pioneers when it comes to school choice” after meeting with school leaders in February.

“They saw that the system wasn’t working, that there was an absence of opportunity, so they took it upon themselves to provide the solution,” she said in a statement.

The comment sparked immediate backlash for “whitewashing” the history of the institutions, formed in response to systemic discrimination that denied black students access to existing schools. DeVos later said that HBCUs were born “out of necessity, in the face of racism.” On Sunday, she issued a statement saying she was looking forward to the commencement, while reiterating her “support for HBCUs.”

“For someone to come and speak at my commencement that cannot relate to me or know what I have been through is kind of like a slap in the face,” graduating student Jasmine Johnson told the Washington Post.

The anti-DeVos petition described her invitation as an “insult” to the legacy of school founder and civil rights activist Mary McLeod Bethune, and the NAACP Florida State Conference called on Jackson to resign.

Bethune-Cookman explained its selection by comparing DeVos to Bethune.

“Her mission to empower parents and students resonates with the history and legacy of Dr. Bethune,” the school said.

During her speech, DeVos called Bethune a “visionary leader” and urged graduates to follow her example and dedicate themselves to service.

Jackson expanded on the decision to bring DeVos to campus in a letter to the community following the initial outcry.

“I am of the belief that it does not benefit our students to suppress voices that we disagree with, or to limit students to only those perspectives that are broadly sanctioned by a specific community,” Jackson wrote. “If our students are robbed of the opportunity to experience and interact with views that may be different from their own, then they will be tremendously less equipped for the demands of democratic citizenship.”

During her speech, DeVos repeatedly pressed students to listen to those with different perspectives:

Spend just a few minutes watching your favorite cable news channel, and you’ll experience the startling polarization happening across the United States. On social media, groups and individuals pit themselves, one against another, not to discuss the merits of deeply help beliefs, but to see who can yell the loudest, score the quickest political points or best silence the other’s voice. The natural instinct is to join in the chorus of conflict, to make your voice louder, your point bigger and your position stronger. But we will not solve the significant and real problems our country faces if we cannot bring ourselves to embrace a mindset of grace. We must first listen and then speak with humility to genuinely hear the perspectives of those with whom we don’t immediately or instinctively agree.

President Donald Trump also met with HBCU presidents in February to promote an executive order affirming the White House’s support for the schools. Some also criticized that meeting as merely a photo op, and his plans for HBCUs came under further scrutiny last week when he suggested that a construction financing program for the schools might be unconstitutional. In a followup statement, Trump said he has “unwavering support for HBCUs and their critical educational missions.”

Trump picked Devos, a billionaire Republican donor and education activist from Michigan, to lead the Department of Education despite her lack of professional experience in public schools. She is a leading backer of the school choice movement, supporting charter schools and voucher programs.