The US will be treating a cyber attack launched against it from any country as an act of war and might retaliate with military force, according to plans to be announced shortly by the Pentagon.
"The Pentagon's first formal cyber-strategy … represents an early attempt to grapple with a changing world in which a hacker could pose as significant a threat to US nuclear reactors, subways or pipelines as a hostile country's military," said The Wall Street Journal.
The Pentagon has itself been a victim of cyber attack in the past as have been many government establishments.
The recent virus attack on Iran's nuclear programme - through the Stuxnet computer worm - added to US worries.
And now the US is ready to fight the cyber battle the traditional way.
The logic behind describing it as an act of wear stems from a belief in the Pentagon that most sophisticated attacks - of the scale to take down a power grid - cannot be carried out without the support of a government.
"If you shut down our power grid, maybe we will put a missile down one of your smokestacks," the journal quoted a military official.
But there is no clarity yet on how the US will determine the origin of the attack and how it will define an attack - what size - as an act of war, the journal said, adding, these issues are being debated in the military.
One view was to determine a cyber attack as an act of war if it caused "death, damage, destruction or high-level disruption that a traditional military attack could cause".
The policy paper - running into 30 classified and 12 unclassified pages - will also discuss the need and stress the importance for the US to synchronize this doctrine with that of its military allies.