Thousands of people flooded city streets from Los Angeles to New York late Monday in passionate – but initially peaceful – protest of 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 slogan that has become a rallying cry in protests over police killings across the U.S.

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 said they were bracing for large demonstrations with the potential for the kind of violence that marred nightly protests in Ferguson after Brown’s killing. Demonstrators there threw Molotov cocktails and police fired smoke canisters, tear gas and rubber bullets.

But police reported that gatherings were mostly peaceful immediately following Monday’s announcement.

Several hundred protesters marched through downtown Philadelphia, yelling “No justice, no peace, no racist police!” A similar protest of about 50 people in Pittsburgh was short-lived, with activists saying they plan to regroup Tuesday at the federal courthouse.

In Los Angeles, which was rocked by riots in 1992 after the acquittal of police officers in the videotaped beating of Rodney King, police officers were told to remain on duty until released by their supervisors. While about 100 people gathered in Leimert Park, others held a small news conference demanding police change their policies and release as quickly as the names of those killed the names of the officers who shot them.

Denver Mayor Michael Hancock urged protesters to be peaceful in that city, where a civil jury last month found deputies used excessive force in the death of a homeless street preacher. Clergy gathered at a church to discuss the decision, and about a dozen people rallied in a downtown park with a moment of silence.

At Cleveland’s Public Square, at least a dozen protesters held signs Monday afternoon and chanted “Hands up, don’t shoot,” which has become a rallying cry since the Ferguson shooting. Their signs references police shootings that have shaken the community there, including Saturday’s fatal shooting of 12-year-old Tamir Rice, who had a fake gun at a Cleveland playground when officers confronted him.

Los Angeles Community activist Najee Ali said he met with police last week to discuss plans for a peaceful gathering in response to the Ferguson decision. The plans include having community members identify any “agitators” who may be inciting violence so officers can remove them from the crowd, he said.

“It was kind of unprecedented,” Ali said of the meeting. “We never collaborate with the LAPD. They do what they do, and we do what we do.”

But since violence erupted at the city’s rallies protesting the shooting of 17-year-old Trayvon Martin in Florida, Ali said there was an effort to avoid repeat problems.

“We told them our plans of protest and we were demanding our First Amendment rights be protected,” Ali said. “They said they’re taking a hands-off approach,” but they’d be in the wings if outside agitators try to stir up violence in the crowds.