Multiple People Shot and Killed at a San Bernardino, Ca Social Services Center

UPDATE: Couple Kept Tight Lid on Plans for San Bernardino Shooting

Police said there may be multiple victims in an active-shooting situation in San Bernardino Wednesday. Sources tell Eyewitness News that up to 12 people were killed.

WATCH: Live coverage of the active-shooting situation in San Bernardino

The shooting took place at the Inland Regional Center, a nonprofit that works with individuals with developmental disabilities, at 1365 S. Waterman Avenue.

Investigators were searching the building and have yet to clear it. Police said there were reports of one to three shooters involved, and they were described to be wearing ski masks.

A source confirmed to Eyewitness News that there were three shooters armed with rifles, and there were no suspects in custody.

Shortly before noon, dozens of people were seen exiting the building with their hands up.

Loma Linda University Medical Center said the hospital's emergency room is in disaster mode and is expecting an influx of patients. The exact number of patients was not immediately available.