A cyberattack that began at facilities operated by California-based Prospect Medical Holdings has disrupted hospital computer systems across the US.

Prospect Medical operates 16 hospitals and a network of more than 165 outpatient facilities and clinics in Connecticut, Pennsylvania, Rhode Island and Southern California.

As a result of the data security incident on 3rd August 2023, Prospect Medical has closed emergency rooms in several states as well as diverted ambulances, reported The Guardian.

In a press statement, Prospect Medical said: "Prospect Medical Holdings, Inc. recently experienced a data security incident that has disrupted our operations.

"Upon learning of this, we took our systems offline to protect them and launched an investigation with the help of third-party cybersecurity specialists. While our investigation continues, we are focused on addressing the pressing needs of our patients as we work diligently to return to normal operations as quickly as possible."

In an emailed statement to The Washington Post, Prospect said that the cyberattack ‘has disrupted’ its operations and is working with the US Federal Bureau of Investigation (FBI) and third-party cybersecurity specialists.

The FBI’s New Haven field office special agent in charge Robert Fuller said that the office is investigating cyber ransomware incidents at some of Prospect Medical’s local medical facilities, reported NBC Connecticut.

The cyberattack has impacted Eastern Connecticut Health Network (ECHN) and Waterbury HEALTH, which are part of Prospect Medical Holdings, reported News 8.

Fuller added: “We are working closely with law enforcement partners and the victim entities to address the issues. At this time there is no further information we can share as this is an ongoing investigation."

Eastern Connecticut Health Network said that all of its elective surgeries and GI procedures will be closed until further notice.