Police on Saturday 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.

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.

Students across the US have rallied or set up tents at dozens of universities to protest the months-long offensive in Gaza and call on President Joe Biden, who has supported Israel, to do more to stop the bloodshed in Gaza. They also demand their schools divest from companies that support Israel's government, such as arms suppliers.

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.

In Los Angeles, police in riot gear swarmed a pro-Palestinian encampment at the University of Southern California early yesterday to clear away demonstrators, after warning everyone to leave the area or be arrested, officials and media reported.

Dozens of people were also 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.

Elsewhere, confrontations did not escalate into arrests. In Ann Arbor, pro-Palestinian protesters briefly disrupted a commencement ceremony at the University of Michigan.

Videos shared on social media showed dozens of students wearing the traditional keffiyeh headdress and graduation caps and waving Palestinian flags as they walked down the centre aisle of Michigan Stadium among cheers and boos from a crowd of thousands.

The ceremony continued and campus police escorted the protesters toward the back of the stadium, but no arrests were made, according to Colleen Mastony, a spokesperson for the university.

Many of the schools across the US, including Columbia University in New York City, have called in police to quell the protests.

Police have so far arrested over 2,000 protesters at colleges around the country.