WASHINGTON — China and ‘‘one or two’’ other countries are capable of mounting cyberattacks that would shut down the electric grid and other critical systems in parts of the United States, according to Admiral Michael Rogers, director of the National Security Agency and head of US Cyber Command.
The possibility of such cyberattacks by US adversaries has been widely known but never confirmed publicly by the nation’s top cyber official.
At a hearing of the House Intelligence Committee, Rogers said US adversaries are performing electronic ‘‘reconnaissance’’ on a regular basis so that they can be in a position to disrupt the industrial control systems that run everything from chemical facilities to water treatment plants.
‘‘All of that leads me to believe it is only a matter of when, not if, we are going to see something dramatic,’’ he said.
Outside specialists say the US Cyber Command also has the capability to hack into and damage critical infrastructure, which in theory should amount to mutual deterrence.
But Rogers, who did not address his offensive cyber tools, said the nuclear deterrence model did not necessarily apply to cyberattacks.
Only a handful of countries had nuclear capability during the Cold War, he said, and nuclear attacks could be detected and attributed in time to retaliate.
By contrast, the source of a cyberattack can easily be disguised, and the capability to do significant damage is possessed not only by nation states but by criminal groups and individuals, Rogers noted.
Rogers’s remarks about critical infrastructure attacks came in response to questioning from Republican Mike Rogers of Michigan, who chairs the intelligence committee.
He asked the NSA director about a private report detailing China-based intrusions into the power grid and other critical systems that appeared to be precursors to attack.