White supremacist groups have targeted college campuses in surging numbers since President Donald Trump’s election, emboldened by political and racial tensions over immigration and other issues, according to a group that monitors extremism and bigotry.

The Anti-Defamation League issued a report Thursday that said racist fliers, banners and stickers were found on college campuses 147 times in fall 2017, a more than threefold increase over the 41 cases reported one year before.

Leaders of the New York-based nonprofit attribute the uptick to a small number of white nationalist groups seeking to recruit members on college campuses that have ramped up their efforts as the nation’s politics grow increasingly polarized.

“Whatever momentum white supremacists felt they had last fall, they certainly are redoubling their efforts,” Oren Segal, director of the Anti-Defamation League’s Center on Extremism, said in an interview.

The league tracked 333 cases since Donald Trump was elected in November 2016. Since then, it has seen increased activity from groups celebrating what Segal called “the divisiveness that was a hallmark of the presidential campaign.”

Dozens of U.S. college campuses have been confronted by far-right groups brandishing racist views over the last year, including an August 2017 rally that drew hundreds of torch-carrying white supremacists to the University of Virginia. Protests there turned deadly the next day, when a car plowed into a crowd of counterprotesters and killed a 32-year-old woman.

Trump drew criticism from Democrats and Republicans in Congress after he insisted that there was “blame on both sides.”

Other rallies followed, including a November demonstration at the University of Texas at Austin led by 25 masked members of a white supremacist group, including some carrying torches and Texas flags.

“What we’re dealing with on college and university campuses is a reflection of the times. It’s regrettable, it’s unfortunate, but that’s where we are in 2018,” said Terry Hartle, a senior vice president at the American Council on Education, which represents chiefs of nearly 1,800 schools.

Although rallies and speeches have drawn the public’s attention, most of the cases tracked by the Anti-Defamation League are quieter efforts from groups that secretly distribute fliers on campus and then leave before they’re found.

Nearly half of the 346 cases tracked since September 2016, for example, have been blamed on the white supremacist group Identity Evropa, whose fliers with messages such as “Protect Your Heritage” have been discovered at universities from New Jersey to California.

In the past month alone, racist fliers have been found at the University of South Carolina and the University of Vermont, and anti-immigration fliers tied to a neo-Nazi group were found at American University in Washington, D.C.

Colleges in Texas have been targeted most frequently, according to the new report, with 61 cases since September 2016. California followed with 43 cases, while Pennsylvania had 18 and Florida had 17.

Schools have responded in a variety of ways. Some sharply condemn hate speech on campus, while others ignore it to avoid drawing attention to white supremacists. It’s often a fine line for colleges that aim to balance free speech with the safety of their students.

Many schools have grappled with whether to allow white nationalist speaker Richard Spencer to speak on campus, including some that now face free-speech lawsuits from his supporters for turning him away.

“Institutions have to contend with legal requirements, practical considerations and moral obligations, and they will respond differently depending on the incident,” Hartle said.

At the University of California, San Diego, for example, members of Identity Evropa reportedly interrupted an ethnic studies class and harassed students on Jan. 11, the report said. The leader of Identity Evropa, Patrick Casey, did not respond to emails requesting comment.

Segal, of the Anti-Defamation League, says numbers are higher in Texas and California because those states house active members from white supremacist groups. He said the numbers don’t necessarily reflect higher numbers of white supremacists at schools in those states.

A total of 212 schools have been targeted since fall 2016, ranging from top Ivy League universities to small community colleges, the report found. Segal says white supremacists typically target schools where they’re likely to stir a strong reaction.

“They very much rely on the surrounding media attention,” he said. “But I think they also hope to reach younger people who might be disaffected, who might be attracted to their message and swell their ranks and secure their future.”