Stonestown Galleria was evacuated Wednesday afternoon due to police activity and a threat that hasn't yet been disclosed — possibly an armed individual — and the SFPD was asking the public to avoid the area.

It's not clear what prompted a mass evacuation of a large mall on San Francisco's west side today, but there was a major emergency response at Stonestown Galleria around 12:30 pm.

SFist co-founder Eve Batey reported from the scene that as of 1:21 pm the mall and the adjacent movie theater remained fully evacuated. And, she says, an SFPD officer on the scene said vaguely, "People call in and say stuff and we have to investigate."

That may be downplaying whatever the actual threat was, but we'll have to wait for further details on that.

The Chronicle reports via police dispatch records that the SFPD was called to the scene at 11:41 am on a report of a person with a gun, but the department has not confirmed that.

San Francisco's Department of Emergency Management issued an alert — which didn't get pushed to all cellphones apparently, because I didn't get it — saying, "Expect traffic delays, consider alternate routes, and allow for additional travel time." The alert only mentions "police activity."

This is the first time in recent SF memory that anything as large as Stonestown Galleria has had to be evacuated over any kind of threat situation.

This is a developing story.

Photo via Google Street View