The shooting was reported Friday afternoon and units have been sent to 838 Brannan and 888 Brannan, fire officials said.
A police spokesperson was not immediately available with more information about the shooting.
David Karner, a customer service specialist at REI, a sporting goods and clothing store located at 840 Brannan St., said employees and customers have been ordered to shelter in place.
Karner said police did not provide any additional details about the investigation.
