Tension in an Occupy Oakland protest.<br/> Police fired tear gas at hundreds of protesters who were trying to take control of a building in downtown Oakland.<br/> Nineteen people were arrested, and three officers were injured.<br/> Police said the clashes erupted when protesters began destroying construction equipment and tearing down the fences of the Henry J. Kaiser Convention Center.<br/> They had vowed to occupy the center to establish a new headquarters.<br/> Police declared an unlawful assembly and told them to disperse.<br/> Oakland Police said officers were pelted with bottles, metal pipes, rocks and improvised explosive devices.<br/> They returned to a plaza after being dispersed, and threatened to march to another abandoned building.<br/> The scuffles are not the first between Occupy Oakland activists and police.<br/> The Occupy Wall Street movement, which originated in New York, is trying to regain lost momentum after protest camps around the country were cleared late last year.<br/> Michaela Cabrera, Reuters.
