The possibility of such cyberattacks by U.S. adversaries has been widely known, but never confirmed publicly by the nation’s top cyber official.

At a House hearing, Rogers says U.S. adversaries are performing electronic “reconnaissance,” on a regular basis so that they can be in a position to attack the industrial control systems that run everything from chemical facilities to water treatment plants.

Outside experts say the U.S. Cyber Command also has that capability, which in theory should amount to mutual deterrence.