BERKELEY — The morning after protests resulted in six arrests and injuries to three police officers, witnesses to the unruliness insisted the number of police present escalated the tension after a person vandalizing with a skateboard touched it off.

They also took exception to any characterization that the protests were violent.

“You know what, it was peaceful except a few dozen people who got out of control,” said Sasha Futran, a 30-year resident of Delaware Street, two blocks from where police and protesters clashed Saturday night. “A very small percentage ruined it for everybody.”

Police said five adults and one juvenile were arrested, but did not say what charges they may face. At least one officer was hospitalized, and two others were hit by bricks, police said. A rock also struck a crime scene technician. They all were expected to be OK.

Three large glass windows at a Trader Joe’s on University Avenue were smashed, as were windows at a Radio Shack about a block away. Both were open Sunday, and there was little evidence of the mayhem at the corner of University Avenue and Martin Luther King Jr. Boulevard, where the chaos started the night before.

No injuries to residents participating in the protest were reported.

The march to mark unrest over the refusal by grand juries to indict officers responsible for the deaths of unarmed black men in Ferguson, Mo., and New York City began around 5 p.m. on Shattuck Avenue. It moved peacefully until reaching University Avenue at the corner of Martin Luther King Jr. Boulevard.

Once the protesters got there, several witnesses said, a male with a skateboard started smashing windows. Looters then charged the Trader Joe’s while one woman tried to block one of the windows and turn them away.

Witnesses estimated the number of protesters at between 1,000-1,500 people, and the police presence at 120-150. Police in riot gear used smoke, rubber bullets and flares to curb the violence, which witnesses said did not ease the tensions.

“It just seemed like an awful lot of officers comparative to the people who were causing trouble,” said 52-year-old Peter Williams, who lives on nearby Berkeley Way. “Berkeley has a long history of protests, and there’s always going to be a small minority who turn violent. But when you have hundreds of police in riot gear, that’s going to get people more agitated, and it seemed to incite things. There’s got to be a better way.”

Protesters threw objects, including pipes and bricks, at police in riot gear. One officer hit with a sandbag during the protests suffered a dislocated shoulder and was hospitalized, Berkeley Police spokeswoman Officer Jennifer Coats said.

A brick hit one officer in the forearm and another in the finger, injuring both, police said. A rock hit a crime scene technician. Police did not say whether they were hospitalized.

Police did not say immediately if they expected protests to continue Sunday night, but according to posts on Twitter, organizers gathered near Sproul Hall and made signs in preparation for a march in case it happens.

“I just want people to realize that this really was a pretty peaceful march,” Futran said. “It’s too bad that a small percentage of people got out of hand.”

Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rderh.