A group of 100 marched through the Mission District in San Francisco to protest the recent killings of unarmed black men by police in the Ferguson and in New York.
"We're just asking for police to be accountable. We give them lots of power, they need to be accountable when using it," said Julie Setelel, one of the protesters.
The march grew as it headed down Market Street, where demonstrators stopped, laid down in the street, blocking traffic in both directions of Market Street near Powell Street.
Nearby, a large group police watched the event unfold and began to arrest people who refused to clear the road. More than 10 people were arrested.
"Our goal is to gather as many people to show that we all against brutality because anyone can be a victim," said Gloria Riva, who was among the protesters.
In downtown Oakland, dozens of windows were boarded up on Broadway, after protesters smashed them during a march on Friday night.
SKY7 HD was overhead as hundreds swarmed onto the I-880, blocking traffic in both directions.
The group later surged into the West Oakland BART station and pounded on entry gates which were closed.
Some small business owners were injured while trying to protect their stores from damage. Alba Navarrete who owns a shoe repair business wants vandalism to stop. "This makes no sense! These things are not going to solve the problem," she said.
Oakland resident Tony Jackson say windows don't need to be broken to bring change. "Dr. martin Luther King did it in the 1960s. They didn't tear stuff up. They had dogs and water thrown on them, but they did it peacefully. This is ridiculous!"