Clashes erupted Saturday between supporters and opponents of President Trump at a park in Berkeley, Calif., where police made a number of arrests.

A group called Liberty Revival Alliance planned a pro-Trump rally at Martin Luther King Jr. Civic Center Park, the Los Angeles Times reported. Anti-Trump protesters also gathered at the site.

The Berkeley Police Department said that it had made more than a dozen arrests as of early Saturday afternoon, and expected to make more. Police also have seized many items that were prohibited from the area.

“A large number of fights have occurred and numerous fireworks have been thrown in the crowds,” Berkeley police said in a news release. “There have also been numerous reports of pepper spray being used in the crowd.”

The police department later said that the protesters were expanding the area of their demonstrations.

Berkeley has been the site of a number of protests in recent months. A pro-Trump event at the Civic Center Park in March also got heated.

The University of California-Berkeley was the site of protests in February as well due to then-Breitbart editor and outspoken Trump supporter Milo Yiannopoulos, who was scheduled to speak at the school.

Updated: 5:40 p.m.