The directive updates one from 2004 as part of an administration push to handle cyberthreats
US President Barack Obama has signed a secret directive laying out new guidelines for cyber-operations that national security planners can use to protect the country's computer networks from attack.
An unnamed senior official told Reuters: "It continues to be our policy that we shall undertake the least action necessary to mitigate threats and that we will prioritize network defense and law enforcement as the preferred courses of action."
James Lewis, a cybersecurity expert at the Center for Strategic and International Studies, said the directive lays out a chain of command and establishes thresholds for action.
"I don't see why the whole thing has to be secret, though," Lewis said.
According to the Washington Post, Obama is said to have signed the directive last month, what the paper identified as Presidential Policy Directive 20.
The directive updates one from 2004 as part of an administration push to handle the growing cyberthreat.
Last month, US defence secretary Leon Panetta had warned that the cyber attckers are developing the ability to strike the country's power grids, financial systems and government systems.
Earlier in October this year, Panetta had warned that the US could face a 'cyber-Pearl Harbor' and drafted new rules which would enable military to move quickly to thwart any such attacks.