OAKLAND, Calif. (AP) -- Police used tear gas and "flash" grenades to break up hundreds of Occupy protesters in Oakland, Calif., after officers say some demonstrators threw rocks and flares at them, tore down fences and ignored orders to leave.
Police say three officers were injured and 19 people were arrested.
Oakland police said in a release that the crowd started assembling downtown Saturday morning and then marched through the streets, disrupting traffic.
The crowd walked to the vacant Henry Kaiser Convention Center, where protesters started tearing down perimeter fencing. Police say they ordered the crowd to disperse at about 3 p.m. and used tear gas after some protesters pelted them with bottles, rocks, burning flares and other objects.
Occupy protesters said earlier this week that they planned to move into a vacant building and turn it into a social center and political hub.