San Francisco police said they shut down part of Nob Hill on Monday because a person was barricaded inside an apartment.
The person is believed to have been brandishing a gun while driving in the area, around 2:45 p.m., police said.
When officers responded to the scene, police said they learned that the person had barricaded themselves in an apartment on the 1400 block of California Street.
Officers then closed off the area near California and Hyde streets.
No arrest has been made yet, according to police.Â