A cyberattack at a California-based healthcare system late last week led to the closure of emergency rooms and forced some facilities to rely on paper records.
The incident began on Thursday at facilities operated by Prospect Medical Holdings, which operates more than a dozen hospitals in states such as California, Texas, Pennsylvania, Connecticut and Rhode Island.
According to its website, the company operates a network of over 160 outpatient centres and clinics.
The attack, on Thursday, led to widespread chaos in those facilities.
Several primary care services remained closed on Friday, while security experts assessed the issue and worked to resolve it.
"Prospect Medical Holdings facilities are experiencing IT complications impacting some of our ECHN locations," the company wrote on its website.
On its own website, Eastern Connecticut Health Network, an affiliate of Prospect Medical, listed several locations that would be closed "until further notice". These included a medical imaging centre, an urgent care facility and an outpatient blood-draw centre, among others.
Emergency departments at Manchester Memorial and Rockville General Hospital remained closed throughout much of Thursday, with patients diverted to other nearby medical centres.
CharterCARE Health Partners, an affiliate in Rhode Island, wrote on Facebook that it had to reschedule certain appointments and revert to using paper records due to the cyberattack.
In Pennsylvania, the attack impacted services at several facilities, including the Crozer-Chester Medical Center in Upland, Delaware County Memorial Hospital in Drexel Hill, Springfield Hospital in Springfield and Taylor Hospital in Ridley Park.
Prospect confirmed the cyberattack in an emailed statement to The Guardian.
"Upon learning of this, we took our systems offline to protect them and launched an investigation," the statement said.
"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," it added.
The company didn't share details about the nature of the attack. However, it said that it was in communication with the FBI and third-party cybersecurity specialists to address the situation.
The healthcare sector, with its sensitive and critical data, has become a prime target for cybercriminals seeking to exploit vulnerabilities and demand ransom payments for the release of encrypted data.
Hackers often deploy ransomware to block an organisation's access to its computer network and then extort money in exchange for restoring access.
In 2022, a cyberattack against One Brooklyn Health, a hospital group in New York, forced staff members to resort to using paper records.
Also last year, CommonSpirit Health, a healthcare system with over 140 hospitals and 700 care sites across the United States, experienced a cyberattack that postponed surgeries and doctor visits.