There appear to be at lest 3 shooters, dressed in Military Style gear with semiautomatic weapons.
As many as 20 people have been shot near a California hospital.
Police are seeking three heavily armed men — who were wearing masks, military-style clothing and possibly body armor — at Inland Regional Center in San Bernardino.
Up to 12 people were killed in the shooting, and at least eight others were wounded. Emergency crews were called about 11:30 a.m. local time to the shooting scene in the 1300 block of South Waterman Avenue.
A bomb squad was sent to dismantle a possible explosive device, and a SWAT team is seeking the gunmen.
The shooting happened several blocks away from a Planned Parenthood clinic, although employees there said the clinic was not a target.
The Inland Regional Center serves the developmentally disabled.
A spokeswoman for the medical center said the shooting took place in a conference room that had been rented Wednesday to an outside group, but she was not sure what organization was in the room.
Police were reportedly conducting a training exercise nearby and were able to respond quickly.
The gunmen may have fled the scene in a black SUV, according to reports.