(CBS) — McLaren Health Care confirmed on Wednesday that a criminal cyberattack caused disruptions to information technology and telephone systems reported on Tuesday.

Officials say it is not known whether patient or employee data was compromised. The IT team is working with security experts to investigate the cyberattack.

“Currently, our facilities are largely operational and able to serve our communities, and will remain so until operations are fully restored. Our emergency departments remain operational, most surgeries and procedures are still being performed, and our physician offices continue to see as many patients as possible,” officials said in Wednesday’s update. “During this time of limited access to our systems, and out of an abundance of caution, some non-urgent appointments, tests and treatments are being postponed.”

On Tuesday, the system reported disruptions and said some non-urgent or planned procedures had to be postponed “out of an abundance of caution.”

Patients at the system’s thirteen hospitals, outpatient surgery centers, physician offices and other service centers – including the Barbara Ann Karmanos Cancer Institute – were advised to keep their appointments while the issue was being addressed unless contacted by a staff member.

McLaren said it took steps to relocate downtown as soon as it was informed of the attack. Officials said they are continuing to operate under downtime measures while systems are restored.

This is the second major technical disruption McLaren has faced in the last year. In 2023, McLaren Health Care said an investigation into suspicious activity on its network found that Ransomware attack.