Mayorkas says White supremacists pose 'most prominent threat' to US homeland

White supremacists pose the biggest terror threat to the United States, Homeland Security Secretary Alejandro Mayorkas said Friday amid a surge of illegal border crossings. 

Citing an "increase in hate" that's spread on social media and other online platforms, Mayorkas further specified that "the most prominent threat is the threat of White supremacists."

Mayorkas made the remarks during a speech at Al Sharpton's National Action Network conference in New York City. The secretary pointed to the "repeated and persistent bomb threats" against Historically Black Colleges and Universities (HBCUs) in recent months as an example of the threats and talked of his recent work with Black universities and churches to improve security.