Incidents of white supremacist propaganda on college campuses in the United States nearly doubled last year academic year, from 165 reported cases in 2016-2017 to 292 in 2017-2018, according to the Anti-Defamation League (ADL).

White supremacists have actively targeted campuses across the U.S. since January 2016, the organization says. Propaganda efforts gained traction in the fall semester of that year and have since "steadily increased."

"We're concerned to see that white supremacists are accelerating their efforts to target schools with propaganda in hopes of recruiting young people to support their bigoted worldview," ADL CEO Jonathan Greenblatt said in a news release on the findings.

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In total since the start of September 2016, ADL has recorded 478 incidents of white supremacist propaganda on campuses, with campuses in California and Texas most frequently targeted. A white supremacist group called Identity Evropa was behind nearly half of the 478 total cases, according to ADL.

Propaganda has included posters, fliers, stickers and banners.

"The propaganda messages range from veiled white supremacist language to explicitly racist images and words that attack minority groups, including Jews, Blacks, Muslims, non-white immigrants, and the LGBTQ community," ADL says. "Some recent examples focus on the baseless perception of danger posed by undocumented immigrants traveling toward the Mexican-American border."