A forthcoming Pentagon report on US cyber security has concluded that some online attacks will be considered acts of war, and could provoke a physical response.
The US military is expected to unveil plans in the next month to extend its reach into the online world with the publication of a review of online strategy.
A report in The Wall Street Journal cited a source as suggesting that a more forceful response to online attacks is likely to become US Army practice.
"If you shut down our power grid, maybe we will put a missile down one of your smokestacks," a military official is quoted as saying.
According to the source, the ideas being discussed are ones of proportionate response. If an online attack causes physical damage to people or property, the response must be no more damaging.
The full document will contain more details, but the military has been taking a much more forceful line on internet attacks of late.
US general Michael Hayden told the Black Hat security conference last year that the military considers the internet to be a new operational theatre, just like any other, and other states are already doing the same.
In the light of the Stuxnet attack, the US isn't the only one preparing for conflict. The UK has rolled out its cyber plans, and NATO is co-ordinating a group to respond against attacks on member states.
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