More than 400 anti-Wall Street protesters were arrested in Oakland during a night of skirmishes in which police fired tear gas and bean bag projectiles, the city said on Sunday, marking one of the biggest mass arrests since nationwide economic protests began last year.
Earlier on Sunday, authorities had said that the arrest figure was between 200 and 300. But the Oakland emergency operations center said in a statement that revised that up to more than 400, and said that Oakland Police were expected to announce a more precise number later on Sunday.
Riot police on Saturday night fought running skirmishes with protesters, injuring three officers and at least one demonstrator.
The scuffles erupted in the afternoon as activists sought to take over a shuttered downtown convention center, sparking cat-and-mouse battles that lasted well into the night in a city that has seen tensions between police and protesters boil over repeatedly.
Oakland has become an unlikely flashpoint of the national "Occupy" protests against economic inequality that began last year in New York's financial district and have spread to dozens of cities across the country.
The protests in most cities have been peaceful and sparked a national debate over how much of the country's wealth is held by the richest 1 percent of the population. President Barack Obama has sought to capitalize on the attention by calling for higher taxes on the richest Americans.
Protests focused on Oakland after a former Marine, Scott Olsen, was critically injured during a demonstration in October. Protesters said he was hit in the head by a tear gas canister but authorities have never said exactly how he was hurt.
The Occupy movement appeared to lose momentum late last year as police cleared protest camps in cities across the country.
Violence erupted again in Oakland on Saturday when protesters attempted to take over the apparently empty downtown convention center to establish a new headquarters and draw attention to the problem of homelessness.
Police in riot gear moved in, firing smoke grenades, tear gas and bean-bag projectiles to drive the crowd back.
"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."
Some activists, carrying shields made of plastic garbage cans and corrugated metal, tried to circumvent the police line, and surged toward police on another side of the building as more smoke canisters were fired.
Oakland city officials said "extremists" were fomenting the demonstrations and using the city as a playground for the movement. Protesters have accused the city of overreacting and using heavy-handed tactics.
Across the country in New York, police said four people were arrested on Saturday night after protesters clashed with police at what demonstrators had called an "OccuParty" inside an abandoned building in the borough of Brooklyn. Protesters knocked over garbage pails and hurled objects at police, slightly injuring six officers, a police spokesman said. The four people were charged with a variety of crimes including inciting a riot.
Tension was rising in Washington as well, where the National Park Service has said it will bar Occupy protesters in the nation's capital from camping in two parks near the White House where they have been living since October.
That order, if carried out as promised on Monday, could be a blow to one of the highest-profile chapters of the movement.