A protest over a US grand jury's decision not to indict a white police officer over the chokehold death of an unarmed black man has turned violent in California, authorities said.

Missiles were thrown at police and windows were smashed in Berkeley as demonstrations around the country continued over the death of Eric Garner.

A spokeswoman for the Berkeley police department said one officer suffered minor injuries on Saturday evening after some of the protesters threw rocks and other objects at police.

She said several businesses were looted and damaged, while local media reported that tear gas and smoke bombs were used to disperse the crowd.

Thousands of demonstrators have protested peacefully in New York and elsewhere since the announcement on Wednesday that a grand jury would not indict a white officer in the death of Mr Garner, a black man who repeatedly gasped "I can't breathe" while he was being arrested for selling loose, untaxed cigarettes. The arrest was captured on video.

Other protests followed a Missouri grand jury's earlier decision not to indict a white officer in the fatal shooting of Michael Brown, an unarmed black 18-year-old.

Mr Garner's family said they have found the scope of the demonstrations and the lack of violence moving.

"It is just so awesome to see how the crowds are out there," said Eric Garner's mother, Gwen Carr, who added that she ended up stuck in her car after protests shut down traffic.

"I was just so proud of that crowd," she added. "It just warmed my heart."

Mr Garner's widow, Esaw Garner, said she saw demonstrators from her apartment window and told her son: "Look at all the love that your father's getting."

Officers have said the outcry over the grand jury decision has left them feeling betrayed and demonised.

Protests continued in New York City for a fourth day with several dozen people lying down on the floor of Grand Central Terminal and marching into shops in Times Square. There were no reports of arrests.

In Seattle, several hundred people marched on the police headquarters.

Authorities said a group split off from the main protest and tried to get onto a roadway. Police said some protesters threw rocks at officers who blocked them from entering it. Seven were arrested.