Protests are roiling college campuses across the U.S. as upcoming graduation ceremonies are threatened by disruptive demonstrators, with students and others sparring over Israel’s military offensive in Gaza and its mounting death toll.

Many campuses were largely quiet over the weekend as demonstrators stayed by tents erected as protest headquarters, although a few colleges saw forced removals and arrests. Many students are demanding their universities cut financial ties with Israel over the large-scale operation in Gaza it says was launched to stamp out the militant Palestinian group Hamas.

Protesters on both sides of the rancourous debate shouted and shoved each other during dueling demonstrations Sunday at the University of California, Los Angeles. The university stepped up security after “some physical altercations broke out among demonstrators,” Mary Osako, vice chancellor for UCLA Strategic Communications, said in a statement. There were no reports of arrests or injuries.

About 275 people were arrested on Saturday at various campuses including Indiana University at Bloomington, Arizona State University and Washington University in St. Louis. The number of arrests nationwide approached 900 since New York police removed a pro-Palestinian protest encampment at Columbia University and arrested more than 100 demonstrators on April 18.