The demonstrations were the latest of several in the area around San Francisco — including in Oakland where activism is strong — to protest recent grand jury decisions in Missouri and New York not to indict while police officers in the deaths of two black men.

Yesterday’s protest began peacefully on the University of California, Berkeley, campus but eventually grew rowdy and spilled into Oakland.

National outrage ... demonstrators stand with tape reading, "I Can't Breathe" — the final words of New York man Eric Garner as he pleaded with police who put him in a deadly chokehold. Picture: Getty/AFP Source: AFP

Activists made their way onto a freeway and blocked traffic.

The California Highway Patrol said officers fired tear gas after protesters targeted them with rocks and bottles and tried to light a patrol vehicle on fire.

Police also said explosives were thrown at officers, but there was no information immediately available on how potent they were.

As hundreds of protesters began marching through downtown Berkeley, the unrest that marked protests Saturday night was touched off again as someone smashed the window of a Radio Shack.

Blocking traffic ... Demonstrators shut down Interstate 195 in Miami, Florida. The protest was one of many that have take place nationwide after grand juries investigating the deaths of Michal Brown in Ferguson, Missouri and Eric Garner in New York failed to indict the police officers involved in both cases. Picture: Raedle/Getty Images/AFP Source: AFP

When a protester tried to stop growing vandalism, he was hit with a hammer, Officer Jennifer Coats said.

Police said groups of protesters late night began roaming through the downtown area, throwing trash cans into streets and lighting garbage on fire, smashing windows on buildings, and damaging and looting businesses.

There also were reports of vandalism at City Hall.

Fighting back ... in this early Sunday, Dec. 7, 2014 photo provided by Gabriel Reyes, a protester stands in front of police, in Berkeley, California. Picture: AP Source: AP

Television footage showed protesters smashing door windows and breaking into buildings and setting rubbish piles ablaze.

Coats said police made five arrests in connection with the demonstrations. She said two officers sustained minor injuries Sunday night.

Coats said in a statement that there was “significant damage” to several Berkeley businesses and that many had windows smashed and several stores were looted.

She said the demonstrations had concluded by about 3.30am.

Fed up ... demonstrators take over an intersection as they march through the Wynwood neighbourhood to protest police abuse on December 7 in Miami, Florida. Picture: AFP/Getty Source: AFP

Meanwhile, seven people were arrested in Seattle Saturday night after protesters threw rocks at police and attempted to block a highway.

Politicians on both sides of the aisle have been calling for calm while activists push for police reforms.

Violence ... in this early Sunday, December 7, 2014 photo provided by Gabriel Reyes, demonstrators face off against police in Berkeley, California. Picture: AP Source: AP

National Association for the Adavancement of Colored People’s president Cornell William Brooks, appearing on political talk show Face the Nation, called for outfitting police with body-worn cameras and changing law enforcement policy.

“We have to change the model of policing,” Brooks said.