Update: The streets are opened up and the suspicious device turned out to be a grenade, which was removed safely. So ... nothing to worry about.
San Francisco police just now alerted us to an incident over in the Mission District: a "suspicious device" was found at about 8:15 a.m. and the bomb squad is on its way to investigate.
According to Officer Gordon Shyy, the device was found on the 3100 block of 16th Street; the entire block has been closed off to all cars and pedestrians.
And yes, your Muni bus is being rerouted, too.
We'll let you know when it's all clear.