On the streets with Portland's Antifa group

<<PLEASE NOTE: This clip contains scenes of violence. VOICED: To some they are violent, dangerous rioters. To others, the last line of defence against the rise of the far right in America. The group Antifa - short for anti-fascists - has grown in prominence since the election of President Trump. Sky News has managed to gain access to this secretive movement, during brutal clashes with the groups they target. Our US correspondent Hannah Thomas Peter has this exclusive report from Portland, Oregon, on the battle taking place on America's streets.>> on January 22, 2018 in Portland, Oregon.