>Oakland police arrested more than 100 Occupy protesters Saturday after they failed to take over a vacant downtown convention center.

Police in riot gear faced off with demonstrators Saturday afternoon at a rally near City Hall. Hundreds of protesters then marched toward the vacant Henry J. Kaiser Convention Center, where they began tearing down the fencing around the auditorium, and police moved to stop them.

By 3 p.m., an area to the west near the Oakland Museum of California was declared an illegal assembly as a thick line of riot-clad officers attempted to disperse the protesters. Police fired tear gas and flash grenades, and some demonstrators responded by throwing rocks and bottles, according to media reports.

PHOTOS: Occupy Oakland

A number of arrests occurred when demonstrators "ignored the dispersal order and assaulted officers," police said. Three officers were reported injured, but no details were released about the injuries.