White supremacists are taking to college and university campuses in an effort to recruit members for their hate groups, The Washington Post reports.

An analysis by the Anti-Defamation League (ADL) described “an unprecedented outreach effort to attract and recruit students on American college campuses.”

The group seeks to document and prevent anti-Semitism and other bigotry. It has tracked 104 incidents since the beginning of the school year in September across U.S. campuses. It also noted a surge in intensity in 2017, with more than half of the documented incidents occurred in January.

“White supremacists have consciously made the decision to focus their recruitment efforts on students and have in some cases openly boasted of efforts to establish a physical presence on campus,” Jonathan Greenblatt, chief executive of the Anti-Defamation League, said in a statement. “While there have been recruitment efforts in the past, never have we seen anti-Semites and white supremacists so focused on outreach to students on campus.”

Some tactics executed by hate groups include flooding campus fax machines with racist fliers, hanging anti-Muslim, anti-immigrant or anti-Semitic posters and visiting campuses to speak with students. So far, incidents have happened in 28 states.

Debra Monroe, a professor at Texas State University, told the Post that multiple rounds of racist posters have showed up on campus. Monroe first saw some after the election.

The Anti-Defamation League attributed many of the national incidents to three groups: Identity Evropa, American Vanguard and American Renaissance.