(Portland, OR)  --  Portland police say opposing groups of protesters are responsible for acts of violence resulting in several arrests.  The groups protesting Saturday included members of Antifa, the Proud Boys and the "HimToo Movement."  Police say the protests weren't planned and there weren't any permits.  A Portland Police tweet says the unlawful assembly turned into a civil disturbance including protesters who allegedly threw milkshakes containing fast drying concrete.  Pepper spray was also in use, both by police and by protesters.  Three people were arrested in the melee.