Education Secretary Betsy DeVos was repeatedly booed and heckled Wednesday when she addressed graduating seniors at Bethune-Cookman University, a historically black college in Florida. Many students turned their backs on DeVos.

Education Secretary Betsy DeVos: “Dr. Jackson, Board of Trustees, thank you so very, very much for this great honor and privilege. I am honored to become a Wildcat. And it’s a real honor and privilege to be with you as we celebrate the Bethune-Cookman University Class of 2017.”

As the booing of Betsy DeVos grew louder, school President Edison Jackson interrupted her commencement address to issue a warning to students.

Edison Jackson: “If this behavior continues, your degrees will be mailed to you.”

Despite the warning, many students kept booing with their backs turned to DeVos. More than 60,000 people had signed petitions opposing the selection of DeVos as commencement speaker at Bethune-Cookman University. DeVos was widely criticized in February when she said historically black colleges and universities are “real pioneers when it comes to school choice.” HBCUs were established because black students were prohibited from attending public colleges and universities throughout much of the United States’s history.