Union officials say 27 protesters were arrested during a march by janitors through San Francisco’s financial district.
The Oakland Police Department has seen a marked increase in the number of juveniles committing crimes this year.
Oakland Police Chief Howard Jordan said residents are looking to take their neighborhoods back.
Three men have been arrested and charged in last year’s shooting death of a San Jose teenager.
A federal grand jury in Oakland recently indicted 40 reputed members and associates of the Burn Out Family Mafia gang for drug trafficking, identity theft and firearm possession charges.
Dozens of people have been arrested in Oakland on drug, weapons and murder charges following a sweep by local and federal authorities.
San Francisco police arrested 68 people on Wednesday in a citywide sweep targeting people on parole or probation who had outstanding warrants.
Of the 40,000 people who signed up to take part in the 101st Bay to Breakers race, fewer than two dozen appeared to run into trouble.
A multi-agency sweep Thursday produced 13 arrests across the Bay Area. Many of those suspects are accused of belonging to the 500 Block-C Street Gang, the same group police have linked to a drive-by shooting in 2010 that killed three suspected rival gang members.
Santa Rosa police have arrested ten Bay Area residents and two from the East Coast in connection with an alleged large interstate marijuana sales, cultivation and distribution operation.