Police in riot gear have used non-lethal weapons on a crowd of more than 1,000 people attempting to march on to Oakland's city hall to condemn arrests made at an "Occupy Wall Street" camp.
Police dispersed the crowd with what appeared to be stun grenades and set off tear gas to drive the demonstrators away from a plaza in Oakland's business district that had been at the centre of Tuesday's conflict.
Ali Winston, a journalist at the scene, described to Al Jazeera the police's tactics.
|Police have used tear gas to disperse anti-capitalism protesters in Oakland [Al Jazeera]
"There have been two incidents of tear gas, flash-bang grenades and less-than-lethal projectiles beanbags being fired at the crowd," he said.
"In one instance, they used CS gas - which is a stronger version of tear gas that affects your respiratory system as well as your eyes, as well as burning your skin. So that's happened twice since then."
While police accuse protesters of throwing large fire crackers at officers, Winston said that had only occurred earlier in the day when police raided and dismantled the protesters' encampment.
"That refers to an incident earlier this morning when the initial camp, when the initial occupation camp, was dismantled by police. Two fire works were set off. I was down there. They were M1000, M80 calibre fireworks.
"Since then, there have been flash-bang grenades lobbed from behind police lines at demonstrators ... anything that's been lobbed after 5:00 am has been a police flash-bang grenade. It happened at least four times."
Witnesses reported seeing several people taken into custody, but an Oakland police spokeswoman said the department would not confirm any arrests until Wednesday.
"It's really, really tense and I think the cops are trying to walk a fine line, but I don't think they are going to back down and neither are the demonstrators," said Cat Brooks, an organiser.
Protest leaders said their march was aimed at reclaiming Frank Ogawa Plaza, which had served as a camp location for two weeks of protests against economic inequality in the city until police cleared it by firing beanbags and tear gas at camp residents.
Demonstrators living in the camp claim to be the Oakland version of the Occupy Wall Street movement launched more than a month ago in New York.
Oakland police arrested 85 "occupy" protesters sleeping in the Frank Ogawa Plaza encampment on Tuesday morning.
Most of the people arrested were taken into custody on suspicion of illegal lodging, a misdemeanour.
Karen Boyd, the Oakland police spokesperson, told Reuters news agency that "those arrested now face charges for camping or assembling without a permit".
|In-depth coverage of the global movement
Boyd said the Oakland police began to clear the plaza before dawn and had "contained" the area within an hour.
About 350 people were in the plaza when police began to clear the area by deploying beanbags and spraying tear gas at the protesters.
Boyd said that there were no reports of injuries. However, protesters and witnesses claim otherwise.
A female demonstrator described her version of the police clearing to a local news agency.
"They were like you, we have a few minutes and then even before the minutes passed they started shooting off. And then, even the fact that everybody left, they kept shooting," the unidentified woman said.
Jean Quan, the mayor of Oakland, said in a statement that she told protesters to cease overnight camping and cooking at the plaza.
"Over the last week it was apparent that neither the demonstrators nor the city could maintain safe or sanitary conditions, or control the ongoing vandalism," Quan said.
The mayor's office said conditions at the plaza had begun to deteriorate by the second week of the protests with police,
fire and medical care reporting they were denied access to the plaza to respond to service calls.
Officials also said that the plaza was damaged by graffiti, litter and vandalism.