Pennsylvania-based hospital chain Universal Health Services (UHS) stated that computer networks at its 250 hospitals that were affected by malware attack are being restored.

Although the firm did not comment on what exactly caused the incident, employees and experts term as a ransomware attack, reported Reuters.

It was reportedly hit by ransomware on 27 September (Sunday).

The cyber attack has impacted its healthcare professionals at the affected hospitals and clinics, many of which are dealing with Covid-19 cases and have to now depend on manual record-keeping, reported ABC News.

Universal Health Services said its “systems were quickly disconnected and the network was shut down in order to prevent further propagation.”

Following the cyber attack, the hospital chain, which has about 90,000 employees, has been experiencing some problems such as longer waiting period at emergency rooms.

According to the company, its electronic medical records systems have not impacted by the breach, and it was continuing to make progress in restoring and reconnecting systems.

The ransomware had shown characteristics of Ryuk, which is linked to cyber criminals in Russia.

It has acute care hospitals in California, Texas, Nevada and Florida.