American Hospital Association or AHA urged healthcare facilities across the United States to disconnect from Change Healthcare, affiliated to insurer UnitedHealth Group, after the healthcare technology firm was hit by a cybersecurity attack.

Change Healthcare said in a statement that a number of its systems and services were affected by the cyber security issue since Wednesday, February 21.

In a regulatory filing on Thursday with the U.S. Securities and Exchange Commission, the company said the issues were caused by a suspected nation-state associated cybersecurity threat actor.

Change Healthcare, which provides prescription processing services, was acquired in 2022 and is now part of UnitedHealth’s Optum. They provide technology services for more than 67,000 pharmacies.

Since Wednesday, Change Healthcare is providing status update, which notes that it is “experiencing a cyber security issue, and our experts are working to address the matter. Once we became aware of the outside threat, in the interest of protecting our partners and patients, we took immediate action to disconnect our systems to prevent further impact.”

The latest update on Thursday said the issue is specific to Change Healthcare and all other systems across UnitedHealth Group are operational, and the disruption is expected to last at least through the day.

The AHA in its statement, said, “we recommend that all health care organizations that were disrupted or are potentially exposed by this incident consider disconnection from Optum until it is independently deemed safe to reconnect to Optum.”

According to AHA, the reported interruption could have significant cascading and disruptive effects on revenue cycle, certain health care technologies, and clinical authorizations provided by Optum across the health care sector. This was due to the sector wide presence and the concentration of mission critical services provided by Optum.

The association also noted that if Optum’s services remain unavailable for an extended period, organizations which utilize Optum’s services should prepare related downtime procedures and contingency plans.