The Pentagon declares war if a cyber-attack threatens civilian casualties.
"A response to a cyber-incident or attack on the US would not necessarily be a cyber-response. All appropriate options would be on the table," Pentagon spokesman Col Dave Lapan told reporters on Tuesday.
The US would "respond to hostile acts in cyberspace as we would to any other threat to our country", stated the White House in plain terms.
"We reserve the right to use all necessary means - diplomatic, informational, military, and economic - as appropriate and consistent with applicable international law, in order to defend our nation, our allies, our partners and our interests."
With notes from BBC World News
