Community water systems in 30 Minnesota towns and cities were hit this week by a "coordinated cyberattack," and details of the attack follow warnings from federal agencies that Iran is targeting critical infrastructure in the U.S. 

Tuesday's advisory from the Minnesota Information Technology (MNIT) stated that the agency was working with federal authorities on the investigation. 

"We have provided relevant information to the federal government, which is evaluating this activity in the broader national context and leading efforts to determine whether it can be attributed to a specific threat actor," John Israel, Minnesota’s chief information security officer, said in a statement. 

In July, the Cybersecurity and Infrastructure Security Agency issued an advisory, warning that Iranian-affiliated hackers were attacking critical infrastructure, including water and wastewater systems. The advisory stresses the importance of "restricting direct internet access."

The guidance in the MNIT advisory recommends that water and wastewater operators "identify operational technology (OT) that can be accessed from the internet and take immediate steps to secure it." 

The agency added that it wasn't aware of any notices asking residents of the communities to modify their drinking water usage.