Thousands of people rallied late Monday in U.S. cities including Los Angeles and New York to passionately but peacefully protest a grand jury's decision not to indict a white police officer who killed a black 18-year-old in Ferguson, Missouri.

They led marches, waved signs and shouted chants of "hands up, don't shoot," the refrain that has become a rallying cry in protests over police killings across the country.

The most disruptive demonstrations were in St. Louis and Oakland, California, where protesters flooded the lanes of freeways, milling about stopped cars with their hands raised in the air.

Activists had been planning to protest even before the nighttime announcement that Officer Darren Wilson will not be charged in the shooting death of Michael Brown.

The racially charged case in Ferguson has inflamed tensions and reignited debates over police-community relations even in cities hundreds of miles from the predominantly black St. Louis suburb. For many staging protests Monday, the shooting was personal, calling to mind other galvanizing encounters with local law enforcement.

Police departments in several major cities braced for large demonstrations with the potential for the kind of violence that marred nightly protests in Ferguson after Brown's killing. Demonstrators there vandalized police cars and buildings, hugged barricades and taunted officers with expletives Monday night while police fired smoke canisters and tear gas. Gunshots were heard on the streets and fires raged.

But police elsewhere reported that gatherings were mostly peaceful following Monday's announcement.

As the night wore on, dozens of protesters in Oakland got around police and blocked traffic on Interstate 580. Officers in cars and on motorcycles were able to corral the protesters and cleared the highway in one area, but another group soon entered the traffic lanes a short distance away. Police didn't immediately report any arrests.

A diverse crowd of several hundred protesters