Police have arrested at least 25 pro-Palestinian protesters and cleared an encampment at the University of Virginia, the university said in a statement, as US campuses braced for more turmoil during graduation celebrations, Reuters reports.

Tensions flared at UVA’s campus in Charlottesville, where protests had been largely peaceful until Saturday morning, when police officers in riot gear were seen in a video moving on an encampment on the campus’ lawn, cuffing some demonstrators with zip-ties and using what appeared to be chemical spray.

The University of Virginia said in a news release that protesters had violated several university policies including setting up tents on Friday night and using amplified sound.

Jim Ryan, UVA’s president, wrote in a message that officials had learned that “individuals unaffiliated with the university” who presented “some safety concerns” had joined protesters on campus.

Dozens of people were arrested for criminal trespass outside the Art Institute of Chicago at a demonstration on Saturday after the institute called in police to remove protesters it said were illegally occupying its property, the Chicago Police Department said on X.