Dueling groups of protesters have clashed at the University of California, Los Angeles, grappling in fistfights and shoving, kicking and using sticks to beat one another. Hours earlier, police carrying riot shields burst into a building at Columbia University that pro-Palestinian protesters took over and broke up a demonstration that had paralyzed the school. After a couple of hours of scuffles between pro-Palestinian and pro-Israeli demonstrators at UCLA early Wednesday, police wearing helmets and face shields formed lines and slowly separated the groups. Police have swept through campuses across the U.S. over the last two weeks in response to protests calling on universities to stop doing business with Israel or companies that support the war in Gaza.