THERE WAS PLENTY of rocking around the City Hall Christmas tree last night.

For about two hours, a group of protesters railing against grand-jury acquittals of cops in the deaths of two men in Missouri and New York were locked in a sonic battle with choirs, dancers and other performers at a tree-lighting ceremony in the City Hall courtyard.

"We're out here protesting against the killing of Mike Brown, Eric Garner and all the other black men who are killed in our streets," Nayo Jones, a member of Black Lives Matter and the organizer of the protest, said at the base of the 35-foot Norway spruce.

"There is no business as usual, no stopping, no resting until there's justice for all black men killed," Jones, 19, screamed above the holiday music blasting from the courtyard's speakers.

The disruption to the festivities followed the trend of last week's protests over the grand jury's decision in Brown's death: peaceful, if not roiling with anger.

Only one arrest was reported, after a protester hopped over a metal barricade into the area in front of the ceremony's stage.

Jones and her group first gathered at 4 p.m. at 30th Street Station. There, about 500 people "died" in solidarity with Brown and Garner, dropping in unison and lying motionless on the floor of the station's main concourse. The silent protest lasted about 4 minutes as commuters braving the evening rush stepped gingerly around them.

The duration was no coincidence: Brown, 18, reportedly had lain for about four hours in the Ferguson, Mo., street after Officer Darren Wilson fired the fatal shots Aug. 9.

Then, as quickly as they had lain down, the group sprang back up, marching out of the station toward Market Street. Amid honking horns and angry shouts from drivers, the group snaked toward the nearby on-ramp for Interstate 76, where they were stopped by police officers.

After a heated exchange, during which protesters screamed at the officers to let them through, the march changed course, heading south on Market.

The sea of people disrupted rush-hour traffic as it took a roundabout tour of Center City, including a loop around Benjamin Franklin Parkway, before rushing into the City Hall courtyard at 6 p.m. as workers were putting the finishing touches on the tree-lighting ceremony's stage.

Jones said the final destination had been planned.

"Mike Brown doesn't get to have a Christmas," she said. "There are more important things than Christmas happening in our streets right now."

At the White House, President Obama responded to the New York grand jury's decision yesterday by saying: "It is incumbent upon all of us as Americans, regardless of race, religion, faith, that we recognize this as an American problem and not just a black problem or a brown problem or a Native American problem.

"When anybody in this country is not being treated equally under the law, that's a problem. And it's my job as president to help solve it."

With megaphones and handmade signs, the Philly City Hall protesters shouted, "No justice, no peace, no racist police!" and, "We can't breathe!" a reference to the last words of Garner, 43, as he was choked by an NYPD officer in July.

Pressed up against a metal barrier in front of the stage, Judy Belt shielded her 5-year-old daughter from the vitriol.

"This is a family event," the incensed West Philly resident said. "I understand you want to protest and get attention, but you can do that anywhere; you don't have to scare kids."

Belt also took offense at the group's attempts to drown out the performers onstage, many of whom were kids themselves.

But the protesters had an answer for that, too.

"I feel empathetic for the kids up there, but we're doing this for them," said "Vision," a vocal protester who was a fixture in both last week's and last night's demonstrations against the grand-jury decisions.

"This is for them," he said. "They may not understand it now, but they will in 10 years.

"Right now, we are not being heard; the system is showing us that black lives don't matter."

In response, the DJ boosted the volume of the music until it echoed powerfully around the courtyard's walls. It made for a surreal scene, a strange mix of calming violin and ukulele notes and the passionate chanting.

As the tree-lighting's 8 p.m. start neared, Desiree Peterkin Bell, Mayor Nutter's director of communications, addressed the crowd, urging the ceremony's "special guests" to be respectful.

"We hear you, but you have to hear us," she said. "Believe me, my heart is aching too."

And when the time came for the final countdown, Nutter and a handful of city officials joined Bell onstage to do the honors, but quickly shuffled away after the spruce's lights sparked to life.

No one stuck around long, protesters included.

"This is not the beginning, and this is not the end," Jones screamed through her megaphone as crews broke down the stage. "There will be other protests."

-The Associated Press

contributed to this report.

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