Pharmacies in Maryland are delayed and may not be able to fill some prescriptions due to a cyberattack on United Health Group, which forces the company to shut down operations.

The United Health Group is one of the three largest businesses that process prescriptions to insurance companies for tens of thousands of pharmacies across the nation.

The attack, which was carried out by nation-state affiliated hackers, is impacting drug stores all over the world.

“Change Healthcare is experiencing a cyber security issue, and our experts are working to address the matter,” Change Healthcare, a company under United Health Group, said in a statement. “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. At this time, we believe the issue is specific to Change Healthcare and all other systems across UnitedHealth Group are operational.”

Pharmacies in Maryland are working to get patients their prescriptions despite the delays.

“Many of them are providing an emergency prescription for a couple of days so that the patient can have their medication for a few days until the system gets back up,” said Aliyah Horton, the executive director of the Maryland Pharmacists Association.

However, some pharmacies around the nation are reporting serious issues.

“This outage is impacting dispensing of pharmacy prescriptions – resulting in delays in processing and in some cases, inability to process. Refills have also been impacted,” Evans Army Community Hospital in Colorado wrote in a Facebook post.

The American Hospital Association is recommending that all healthcare organizations impacted or possibly exposed disconnect from the system until it is deemed safe.

“Organizations should use this opportunity to test the security, redundancy and resiliency of their network and data backups ensuring they remain offline,” the AHA wrote in a statement.