On Sunday, the Los Angeles Police Department said there were a total of 75 arrests after the protest.
The event was supposed to end at 5 p.m. Saturday, and the arrests were made after a dispersal order was given at 5:30 p.m.
According to LAPD, protesters were attempting to tear down a chain-link fence blocking the Metropolitan Detention Center and throwing items over the fence toward officers. As tensions with federal officers escalated, dispersal orders were issued, and unlawful assembly was declared. At one point, LAPD was also on a Tactical Alert.
After the dispersal order was issued, officers began using tear gas to get the crowd under control.
By about 9 p.m., it appeared things had mostly calmed down in the area, and the Tactical Alert for LAPD ended.
Breakdown of arrests, according to LAPD
75 total arrests - 66 of the people who were arrested are adults and were arrested for failure to disperse. One person was arrested for possession of what was described as a dirk or a dagger. Eight juveniles were also arrested for failure to disperse.
Police said an unlawful assembly was declared after protesters threw rocks, bottles and pieces of concrete at federal officers. LAPD reported that rocks were also thrown at its officers, leaving several with minor injuries.
Earlier in the day, the "No Kings" protest drew tens of thousands who listened to speakers before marching peacefully through downtown streets. It was after the official rally ended that the smaller group of agitators began facing off with agents outside the Federal Building.
National organizers called Saturday "the largest single-day nonviolent protest in modern American history," saying at least 8 million people participated at more than 3,300 events across all 50 states and on nearly every continent.
Protests were scheduled in cities across Southern California, but the largest was at Gloria Molina Grand Park, across from City Hall, in downtown Los Angeles.
Chaos unfolds after thousands gathered for DTLA 'No Kings' rally
Local demonstrators said they joined the march out of concern for the country's political direction.
"I spent four years in the Army turning around trying to fight what's happening in our country right now," said Don Napoli. "You've got somebody that is in total power that is overwriting our constitution."
Patrick Feliciano, another attendee, said, "I feel like our administration is currently taking us down a path of fascism, and I feel like it's destroying our democracy."