Masked protesters smash windows, injure 2 officers in Berkeley, California

(CNN) -- Protests turned violent in northern California early Sunday when some masked demonstrators smashed windows while others pelted officers with rocks and bottles, authorities said.

Police said about 200 people were on Berkeley streets for another day of protests over a grand jury

decision not to indict New York City Officer Daniel Pantaleo for Eric Garner's death on July 17.

But as some broke windows at businesses in the city, other protesters implored them to stop the violence.

Police in riot gear lined the streets while others hovered nearby on motorbikes. They warned crowds to disperse, but some vandalized various businesses, including a Trader Joe's and a Wells Fargo Bank, police said.

Authorities used teargas to break up the crowds, said Jennifer Coats, a spokeswoman for the Berkeley Police Department.

"A small portion of protesters have been violent. They started throwing rocks and other projectiles at our officers," Coats said.

Two officers suffered minor injuries as a result, including one who was treated for a dislocated shoulder.

Garner's mother to protesters: 'Keep on doing it, but do it in peace'

Nationwide protests

Protesters have taken to the streets nationwide, outraged over the decision not to bring charges against Pantaleo, whose chockhold led to Garner's death.

"What's happening in these cities in these last several days is incredibly important to show we have a unified voice," said Judi Flournoy, who was participating in a New York protest.

Garner's mother, Gwen Carr, has urged demonstrators to "keep on doing it, but do it in peace."

In New York, the victim's widow, Esaw Garner Snipes, has said watching the mass of demonstrators from her Staten Island home brings tears to her eyes. She said she told her son, "Look at all the love your father is getting."

On Saturday, dozens of protesters staged "die ins" -- lying down on the ground in memory of Garner -- at Grand Central Station in Manhattan and Union Station in Washington.

Meanwhile, New York officials said complaints against police officers fell significantly in the second half of the year, compared with July to November 2013.

A report that tallied complaints said 1,813 were made so far since July 1 of this year, 26% fewer than the number of complaints filed with the Civilian Complaint Review Board in the same period of the prior year. Excessive force allegations fell by 29%.

The dip followed a slight rise in the first six months of the year, the report said. But overall, allegations have declined in 2014.