Things turned ugly overnight in Oakland.
Police and and a small group of protesters clashed on Broadway in downtown Oakland as a largely peaceful general strike day, which included a shutdown of the Port of Oakland, ended in a near riot.
The group was about 7,500 strong before it dwindled down to the the hundreds around 11 p.m. Reporters said things got violent after midnight.
Protesters started a large bonfire in the middle of the street, forming a barricade of large trash bins, with police in riot gear moving in on the hundreds of protesters as flames leapt high in the air.
Police warned protesters to leave before firing several rounds of tear gas and “flash bang” grenades.
As the barricade at Broadway and 16th Street burned, a fire truck arrived to extinguish it as the scene turned chaotic, The Oakland Tribune reported.
Some protesters wearing cloth wrapped around their faces marched as they chanted, "Whose streets? Our streets." Others wore gas masks.
Just after the clash, police and protesters, just a few feet apart, stared each other down in a tense standoff. A couple dozen people sat on the ground in front of the police, some with their heads bowed as in prayer.
Officials said protesters began hurling rocks, explosives, bottles and flaming objects at officers. Dozens of protesters wielding shields were surrounded and arrested.
Earlier, at about 10:30 p.m., protesters took over the vacant Traveler's Aid Society building at 16th Street and Telegraph Avenue. The organization helped the homeless, but its government funding was cut, and the building was foreclosed upon.
"Since 10, the space sat vacant, as though it were disposable to those with the keys," said a flier protesters distributed, according to the Tribune. "To us this space is invaluable. We are reclaiming it for the people. It is now open for our use."
That building was cleared by 2 a.m., according to reports.
By early Thursday morning, protesters were at the scene of several businesses that had been vandalized trying to clean up the mess.
NBC Bay Area reporters who arrived on the scene before sunrise on Thursday found a lot of vandalism on both private and city buildings.
Graffiti covered nearly every building between 14th and 15th Street along Broadway near the Rite Aid store.
The Tully's coffee shop at Frank Ogawa Plaza had broken windows. Occupy protesters put up boards on the Tully's window in order to keep looters out.
Windows at the Men's Wearhouse store in Frank Ogawa plaza were smashed despite the store closing Wednesday and putting up a sign supporting the demonstrations.
On other stores, Occupy protesters put up signs condemning the vandalism.
They also hung up signs that said that the damage was not done by the people. The Oakland Police Department has blamed a splinter group of anarchists for the damage
Damage estimates were not immediately available.