In Oakland, California, just east of San Francisco, peaceful protesters are detained and arrested for taking to the streets after curfew.
"This is a follow-up to a very peaceful demonstration that we saw this afternoon. We saw hundreds of young people from Oakland walking on the streets. There was a rally at a local high school and then they came to the center "city," said CNN correspondent Dan Simon at the scene.
The Oakland Police Department said in a tweet that it had detained more than 40 people for violating the curfew and urged people to stay at home.
The curfew came into effect at 8 p.m. local time, and will remain in place until 5 a.m. Tuesday morning.
It's not just Oakland: Farther south, along California, Los Angeles police also arrested protesters who were absent after the curfew. A small crowd was arrested on Sunset Boulevard in the middle of Hollywood, hands held by ties.
Officers in police cars were seen shouting through their windows that it was a curfew, and that those who were still outside would be arrested and locked.
Los Angeles police said on Twitter that "dozens" had been arrested for burglary after blowing snow had been looted earlier today.
Mayor of Oakland on freedom of protest: Oakland Mayor Libby Schaaf acknowledged earlier today that there is a painful history of curfews in America used as a form of government oppression - but that it was about security and not censorship.
"I want to be clear that this is in no way to stifle what we are passionate about and that is freedom of expression and protest," she said.
