About six protesters had chained themselves to the front entrance of the building at 1515 Clay St. around 8 a.m. in solidarity with hundreds of California prison inmates who stopped eating on July 8 over the issue of solitary confinement.
Other protesters stood nearby, chanting and carrying signs. Workers were able to enter the building through a back entrance.
Just after 11 a.m., the protesters moved inside to the building's lobby, group spokesman Carl Patrick said.
Once inside, they were told that if they didn't leave by noon they would be arrested, Patrick said.
He said the group is calling on Gov. Jerry Brown and the California Department of Corrections and Rehabilitation to enter into "meaningful negotiations" with the prisoners.
"We primarily are here to end torture," Patrick said this morning. "We believe that long-term solitary confinement is torture."
CHP Officer Sam Morgan said that just after noon, seven of the people sitting the lobby were arrested, he said.
The protest cleared out after the arrests and no demonstrators remained on the premises, he said.