(Portland, OR)  --  Portland police say vandalism and violence that punctuated an anti-Trump protest was perpetrated by anarchists.  The protest started peacefully at five p.m. yesterday at Pioneer Courthouse Square, but demonstrators began marching later and proceeded to block traffic.  Numerous instances of vandalism were reported, and authorities say people began hurling projectiles at officers.  Police in riot gear used flash-bang devices to force rioters to disperse and rubber bullets to split up the crowds.  Authorities told KOIN-TV members of anarchy groups blended in with the crowds and used the opportunity to break the law.