Riot police fought running clashes with Occupy Oakland protesters on Saturday, arresting more than 200 people and firing tear gas in scuffles that injured three officers and at least one demonstrator in the California city.

The confrontations erupted in the mid-afternoon as Occupy activists sought to take over a shuttered convention center, attempting to regain momentum in their movement against economic inequality after authorities cleared protest camps across the country late last year.

Hundreds of people filled the downtown Oakland streets well into the evening, turning their anger toward authorities in a city that has seen simmering tensions between police and protesters boil over repeatedly.

Occupy Oakland has got to stop using Oakland as its playground, Mayor Jean Quan said at a late-evening press conference as officers in riot gear were still lined up against demonstrators in parts of downtown.

Once again, a violent splinter group of the Occupy movement is engaging in violent actions against Oakland, Quan said.

City officials said three police officers and one protester were injured during repeated altercations throughout downtown. There was no immediate word on their condition. Streaming Internet broadcasts by activists showed several demonstrators being treated by paramedics or loaded into ambulances.

Occupy Oakland organizers had earlier vowed to take over the apparently empty convention center to establish a new headquarters for their movement and draw attention to homelessness in a move seen as a challenge to authorities who have blocked similar efforts before.

Police and protesters first scuffled after activists tried to tear down a chain-link fence surrounding the Henry J. Kaiser Convention Center in downtown Oakland.

The one percent have all these empty buildings, and meanwhile there are all these homeless people, protester Omar Yassin told Reuters at the scene.

Police in riot gear moved in, firing smoke grenades and tear gas to drive the crowd back. A city representative estimated the number of arrests at more than 200 throughout the day.

Officers were pelted with bottles, metal pipe, rocks, spray cans, improvised explosive devices, and burning flares, the Oakland Police Department said in a statement. Oakland Police Department deployed smoke and tear gas.

Corrugated Metal Shields

Some activists, carrying shields made of plastic garbage cans and corrugated metal, tried to circumvent the police line, and they surged toward police on another side of the building as more smoke canisters were fired.

The City of Oakland welcomes peaceful forms of assembly and freedom of speech, but acts of violence, property destruction, and overnight lodging will not be tolerated, police said in a statement.

Hundreds of demonstrators regrouped and marched through downtown Oakland, where they were repeatedly confronted by police in riot gear. Police at several points fired flash-bang grenades into the crowd and swung batons at protesters.

A group of demonstrators ultimately made their way to City Hall, where they brought out a U.S. flag and set it on fire before scattering ahead of advancing officers.

Several hundred people remained in the streets well after dark, facing off against lines of riot police holding batons who demonstrators sometimes taunted as pigs.

Protesters in Oakland loosely affiliated with the Occupy Wall Street movement that began in New York last year have repeatedly clashed with police during a series of marches and demonstrations.

In October, former U.S. Marine Scott Olsen was left in critical condition with a head injury following a confrontation with police on the streets of Oakland in which tear gas was deployed.

Organizers said Olsen was struck in the head by a tear-gas canister. Authorities opened an investigation into that incident, but they have not said how they believe he was hurt.

Elsewhere, the National Park Service said on Friday it would bar Occupy protesters in the nation's capital, one of the few big cities where Occupy encampments survive, from camping in two parks where they have been living since October.

That order, taking effect on Monday, was seen as a blow to one of the highest-profile chapters of the movement.

(Additional reporting by Dan Whitcomb and Mary Slosson; Writing by Dan Whitcomb; Editing by Cynthia Johnston)