TAIPEI (Taiwan News) — Mackay Memorial Hospital in Taipei faced a ransomware attack on Sunday, marking the first case of such an attack on a medical center in Taiwan.

According to the Ministry of Health and Welfare (MOHW), the ransomware encrypted hospital files, making patient records inaccessible, per CNA. Encryption is a way to scramble data to make it harder for someone to steal, but it can also be used by hackers as a bargaining tool.

The virus spread through the system, causing over 500 computers in the hospital’s outpatient and emergency departments to crash. Hackers threatened with a second attack on Tuesday at 5 p.m., and CNA reported their demands were not disclosed as the case is ongoing.

According to a Tuesday statement, the hospital started emergency procedures upon learning about the virus on Sunday, per Liberty Times. MOHW Department of Information Management Director Lee Chien-chang (李建璋) said the health ministry coordinated with the Ministry of Digital Affairs’ Administration for Cyber Security, requesting experts to be stationed at the hospital to guard against the second wave, per RTI.

Meanwhile, virus signatures were shared with other hospitals, and local antivirus companies coordinated to update virus databases for interception. As of reporting time, the virus has been removed from the hospital’s system, and no personal data breaches have occurred.

Lee said the ministry briefed cybersecurity officers at hospitals nationwide about the attack and issued directives for preventive defense measures. Since some hospitals operate on outdated systems, they may still be vulnerable, he added.

To address this, Lee said the health ministry has coordinated with vendors to provide free proactive defense systems for 60 hospitals.

Preliminary information suggests that the attack may have originated from Russia, but its intent remains unclear, CNA reported. The hospital condemned the attack and said it is committed to strengthening cybersecurity.