In a blog post published on Saturday, Microsoft Corp stated that it discovered damaging malware in systems belonging to many Ukrainian government agencies and organizations that collaborate closely with the Ukrainian government.

According to Microsoft, the malware’s victims include Ukrainian government entities that offer crucial executive branch or emergency response operations.

An information technology business that administers websites for public and commercial sector clients, including government institutions whose websites were recently vandalized, was also impacted. Microsoft did not name the IT firm that was engaged.

The malware assaults did not exploit any weakness in Microsoft goods or services, according to the US software giant, which discovered them on Thursday.

On Thursday night, a major cyberattack targeted government websites, advising Ukrainians to “be terrified and anticipate the worst,” rendering several websites unusable on Friday morning and leading Ukraine to launch an inquiry.

According to a senior Ukrainian security officer, Ukraine thought a hacking organization associated to Belarus intelligence carried out a cyberattack and used malware identical to that employed by a group linked to Russian intelligence.

The virus, disguised as ransomware, would render the compromised computer system useless if activated by the attacker, according to Microsoft, who added that the business will continue to collaborate with the cybersecurity community to identify and help targets and victims.