Federal agencies warned that cyber attacks targeting municipal water systems were reported in seven states this week.

The FBI and the EPA issued the nationwide warning after hackers targeted more than 30 municipal water facilities in Minnesota. Officials said they believed the hackers were trying to cause a loss of system pressure, which could lead to possible contamination of the water supply.

At a cabinet meeting, President Trump pointed blame at Minnesota authorities.

"We heard in Minnesota there was a cyber attack and they blame it on Iran. I don't think so. I think I blame it on Minnesota because they're grossly incompetent. There was a cyber attack of 30 water plants, and I would blame it on Minnesota and the governor, the corrupt governor of Minnesota. They like to say, oh, it's Iran. Iran should be so lucky. Iran's got bigger problems than worrying about Minnesota," Trump said.

In a public service announcement, the agencies said water and wastewater utilities had reported incidents to the FBI, with some malicious activity negatively affecting water operations.

The announcement did not identify the other states affected so far.