Update: Union Square has now been reopened, the suspicious device was deemed to not be an explosive.
Original Story: San Francisco police shut down and evacuated Union Square this morning after a suspicious device was located at Geary Boulevard and Stockton Street
Officer Gordon Shyy says the initial call came in at about 11:50 a.m., prompting police to evacuate all of Union Square. In addition, a one-block radius around Union Square is currently closed to cars and pedestrians. Also Muni isn't stopping around Market and Fourth streets, according to Muni officials.
Cops are at the scene now. We'll tell you more when we know more.