The Obama administration struggled over the weekend to strike an appropriate public response to the devastating computer hack against Sony, as officials scrambled behind the scenes to come up with ways to retaliate and prevent future attacks.

Publicly, President Barack Obama turned down the rhetorical heat against North Korea, which the US blamed last week for the hacking of Sony’s computer systems and prompting it to cancel the release of a movie satirising the dictatorship. “I don’t think it was an act of war, it was an act of cyber-vandalism that was very costly, very expensive,” Mr Obama said in an interview shown on CNN yesterday.

His attempt to put a more moderate interpretation on a rare publicly identified cyber attack by a foreign government against a target in the US brought immediate condemnation from political opponents.