In Berkeley, California, police used tear gas and fired rubber bullets at hundreds of demonstrators and bystanders Saturday night at a protest against police violence.

Two people had already been arrested the night before at a protest over a New York grand jury’s decision not to charge Daniel Pantaleo, the police officer who killed Eric Garner in Staten Island. Students have also been protesting the recent 27 percent tuition hike at the University of California system during the past two weeks.

After an initial series of protests and rallies in the downtown area, involving as many as a thousand people, a column of at least 60 police officers clad in riot gear confronted a group of overwhelmingly young and peaceful protesters outside UC Berkeley on Telegraph Avenue, one of the main thoroughfares of the city. The police charged the group of students using tear gas, batons, riot shields, smoke grenades and rubber bullets.

Hundreds of people could be heard screaming and fleeing the scene, trying to escape the tear gas, which hung like a toxic cloud over the whole area. The gas was strong enough that it poured into the nearby residential streets where large groups of bystanders were watching the confrontation. Groups of residents, primarily students, came out of their homes to treat the afflicted.

According to the Daily Californian, the student-run newspaper, two Berkeley students required serious medical attention due to the police response. One woman, according to the San Francisco Chronicle, had a seizure and was then stepped on by a line of advancing cops. Another man broke his leg during the protests.

Marcel Davis, a 22-year-old man, also had a seizure. He told the Daily Californian that he was hit by the police with a baton. A police spokesman said that at least five people over the age of 18 and one under 18 were arrested.

A group of older concert-goers was also caught in the police charge. Elaine Dunlap, age 74, and her husband were tear gassed by the police. She told the Associated Press, “I’m not sure that’s necessary. … I think people have a right to protest, certainly for an issue as big as this.”

Officer Jennifer Coats, the Berkeley Police Department spokesperson, justified the police violence against the peaceful protest by pointing to activities earlier in the night when the protest was concentrated in the downtown area. Three storefront windows had been broken and rocks had been thrown at police and police vehicles. According to Coats, a police officer required hospitalization.

The overwhelming majority of the protest was peaceful, however. At one point a crowd of students restrained an individual from breaking a window. In Oakland, on the previous day, police were accused of planting undercover cops at an Eric Garner protest by users on Twitter who shared photos of alleged undercover cops in and out of uniform.

The protest in Berkeley was one of a number of ongoing demonstrations throughout the country over the weekend. In Seattle, Washington, police clashed with protesters on Saturday, arresting at least seven.

In Pittsburgh, about 300 people attended a rally against police brutality at the University of Pittsburgh Friday evening despite a cold rain.

Approximately 300 students participated in a march on Friday at SUNY Geneseo, a public liberal arts school of 5,300 students. The protesters chanted “I can’t breathe, we can’t breathe, Geneseo can’t breathe;” “no justice, no peace,” and other chants.

Alex, a political science major, said, “I’m here mainly because I see police brutality being accepted and supported by the bureaucracy.”

Serrana said, “I don’t agree with police brutality. I feel like everyone’s lives matter, and that we have an opportunity to voice our opinions.”