The US will show "restraint" in cyber operations outside of US government networks, Secretary of Defense Chuck Hagel says, urging other countries to do the same.
Hagel, speaking at the National Security Agency (NSA) headquarters at Fort Meade, Maryland, said the Pentagon "does not seek to 'militarise' cyberspace".
Instead, Hagel said the US government "is promoting the very qualities of the internet - integrity, reliability, and openness - that have made it a catalyst for freedom and prosperity in the United States, and around the world".
The remarks came at the retirement ceremony for outgoing NSA chief, General Keith Alexander.
Hagel also said the US would "continue to take steps to be open and transparent about our cyber capabilities" with Americans, US allies "and even competitors".
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The idea is to "use the minimal amount of force possible" in cyber operations, a senior defence official told reporters, speaking on condition of anonymity.
This would take place only when it would "either prevent conflict, de-escalate conflict or allow us to use the minimal amount of force".
"That is not always the approach that other nations in the world use," the official said.
Alexander's successor is a US Navy officer, Vice Admiral Michael Rogers.
Hagel is set to begin a tour of Asia next week with a stop in China, where cyber-spying will be a hot topic following a report in The New York Times and Germany's Der Spiegel that the NSA had secretly tapped Chinese telecoms giant Huawei for years.
The NSA had access to Huawei's email archive, communications between top company officials, and even the secret source code of some of its products, according to the reports based on information provided by fugitive former NSA contractor Edward Snowden.
