Following recent activity by white supremacist groups Patriot Front and Vanguard America on several U.S. college campus, the Anti-Defamation League today released a study that shows “an alarming increase” in white supremacist propaganda at universities in this country.

According to the survey by the ADL’s Center on Extremism, 346 incidents of white supremacist propaganda took place on 216 campuses since September 1, 2016. These incidents include fliers, stickers, banners and posters.

The ADL study found a 258 percent increase in such incidents during the fall 2017 semester (41 to 147), compared to the fall 2016 semester.

“White supremacists are targeting college campuses like never before. They see campuses as a fertile recruiting ground,” said Jonathan Greenblatt, CEO of ADL.

Protesters are held behind a line of police as they react to white nationalist Richard Spencer, who popularized the term “alt-right” speech at the Curtis M. Phillips Center for the Performing Arts on October 19, 2017 in Gainesville, Florida. Getty Images

Identity Evropa, which focuses on the preservation of “white American culture,” was responsible for 158 of the incidents in the last year, the survey reported.

In addition, Richard Spencer, a prominent racist, has given several public speeches at U.S. universities during the past year, and is scheduled to appear at Michigan State University next month.

“While campuses must respect and protect fee speech, administrators must also address the need to counter hate groups’ messages and show these bigoted beliefs belong in the darkest shadows,” Greenblatt said. “There is a moral obligation to respond clearly and forcefully to constitutionally protected hate speech.”