Banner day for OWS.

(Reuters) — 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.