Washington — GOP Rep. Mike Turner of Ohio said on Sunday that critical infrastructure assets “need to be hardened” as federal investigators probe whether Iranian hackers were behind malicious cyber activity that affected technology at water systems in Minnesota and several other U.S. states last week. 

The FBI said last week that at least seven states have reported cyber activity, which forced some utilities to switch to manual operations and prompted investigators to look into whether the activity is the work of Iranian hackers, U.S. officials and sources familiar with the incident told CBS News. 

Meanwhile, President Trump said he didn’t think the Iranians were behind the attack, claiming that Minnesota, one of the states that reported the incidents, was responsible. He called the state’s leadership “grossly incompetent” while pointing without evidence to Democratic Gov. Tim Walz.

Turner, who previously chaired the House Intelligence Committee, told “Face the Nation with Margaret Brennan” that Congress has not been informed about the incidents. But he said Iran has “attacked our critical infrastructure previously,” in addition to reports of Chinese and Russian hacking. Iranian state-sponsored hackers have been accused of carrying out cyberattacks on U.S. companies, government agencies and infrastructure for more than a decade.

“One thing that we have to acknowledge is that our adversaries — Russia, China, North Korea, Iran — look at the critical infrastructure that support our civilian infrastructure, like water, … as valid military targets,” Turner said. “These are things that we do not do, we would not do, and Iran certainly has been doing this well before this conflict, and this is something we certainly need to be aware of.”

Turner added, “We’re certainly in a conflict where we would expect that they would continue that if they were doing to us before.”