Police, protesters clash as U.S. cities endure violent weekend

Protests took a violent turn in several U.S. cities overnight, with demonstrators squaring off against agents outside a federal courthouse in Portland, Ore., forcing police in Seattle to retreat into a station house and setting fire to vehicles during unrest in California and Virginia.A protester in Austin, Texas, who was apparently armed with a rifle was shot and killed after witnesses say he approached a car that had driven through a march against police violence. And someone was shot and woun