Michigan on Saturday has reported cyberattacks targeting nine of its water systems, joining neighboring Minnesota, where more than 30 systems were recently affected, as the FBI investigates the incidents amid concerns over Iranian-linked cyber threats.

Michigan officials said the state received a federal cyber alert on Tuesday warning of attempts to compromise operational technology used by water utilities. Shortly afterward, several communities reported suspicious activity matching the federal warning.

Dale George, communications director at Michigan’s Department of Environment, Great Lakes, and Energy, said nine water systems were impacted but all continued operating safely. He said local operators resolved the issues and there were no known public health risks.

The FBI said it is working with federal partners to protect critical infrastructure but has not identified those responsible. Last week, the FBI and the Cybersecurity and Infrastructure Security Agency warned that Iranian hackers have increasingly targeted water and wastewater systems and other critical infrastructure.

Minnesota officials said most confirmed attacks involved remote monitoring and control technology rather than direct disruption of water services. Braham briefly asked residents to reduce water use after a cyberattack shut down its water treatment controls, while Plymouth restored communications after a separate attack.

President Donald Trump blamed Minnesota officials for the incidents without providing evidence, prompting Democratic Gov. Tim Walz to respond that Trump knew the attacks had affected multiple states.