Someone has been attaching posters to bulletin boards on Penn State University's main campus that tell people to report illegal immigrants.
University officials said they do not know who is behind the signs and denounced them as "deeply offensive" in a statement.
"The posters are unsigned and appear to be designed to provoke anger, fear and hate," it said.
Likewise, U.S. Immigration and Customs Enforcement officials called the signs "bogus," saying Friday that the agency was not involved and would not solicit information in that manner.
Penn State officials said signs that were affixed to bulletin boards that are intended for use only by university organizations are being removed. But some of the posters are on public boards and, in keeping with routine practice, they will be left alone unless they block other notes.
"As an institution of higher education, Penn State fully supports the right of free speech and encourages its expression in thoughtful and respectful ways, even when we strongly disagree with the opinions expressed," the school's statement read.
Penn State officials did not specify where on campus the posters were hung.
The signs surfaced at a time of increasing campus angst over federal immigration policies promoted by President Donald J. Trump, including a temporary ban on immigration from seven Muslin-majority nations. That ban, instituted last month, so far has been blocked by federal courts.
"These recent developments affect not only our international students and faculty, but also every one of us," Penn State President Eric Barron said in a statement issued just after the ban was announced.
Similar messages have gone out from leaders of other colleges and universities.
Shortly after the ban was announced, Mr. Barron advised non-U.S. citizens at Penn State to carry proof of immigration status when traveling within this country and suggested that individuals avoid leaving the country if possible, since some could face difficulty returning.
When told of Penn State's approach to removing some but not all the posters, Witold Walczak, legal director for the ACLU of Pennsylvania, said Penn State appeared to have struck the proper balance in acting without infringing upon free speech.
It's not just the signs that potentially cause unease but "the whole anti-immigrant climate that we're in,'' he said. "You generate fear and cause people to be suspicious of, and antagonistic to, people because they look and sound different."
The student newspaper, The Daily Collegian, said images of the posters were circulating on social media earlier this week. It published an image that included the message, "It is your civic duty to report any and all illegal aliens. They have broken the law."
Penn State, in its statement, said "every student on this campus has earned the right to be here based on their academic qualifications and hard work."