Scripps Health confirmed Sunday their technology servers were hacked overnight, forcing the health care system to switch to offline chart systems and causing a disruption to their patient portals.
Scripps did not provide any information on how the cyberattack occurred or state exactly what systems were affected by the breach.
The health care system said they suspended access to their patient portals and other "technology applications related to our operations at our health care facilities," but stressed that patient care continues using "established back-up processes, including offline documentation methods."
Scripps website was down Sunday morning and patients were reporting to NBC 7 that their patient portals were not working.
Some appointments were being canceled on Sunday and Monday as a result of the breach.
"We are working on how best to notify these patients about the need to reschedule," a statement from Scripps said.
The San Diego County Office of Emergency Services (OES) said ambulances were being diverted from Scripps' facilities to other hospitals in the area but that it was a precautionary measure.
Scripps said that outpatient urgent care centers, Scripps HealthExpress locations and their emergency departments remain open for care.
Local law enforcement and "the appropriate government organizations" were notified of the cyberattack, Scripps Health said.
The OES said their cybersecurity professionals were actively investigating.
This is a developing story and will be updated.