The US is considering responding to hackers through the use of conventional weapons, according to the director of the National Security Agency (NSA).
Michael Rogers, who also heads US Cyber Command, told a forum in Washington DC that the American military was contemplating several options as it prepares for the rising risks of cyber.
Speaking at George Washington University, he said: "Because an opponent comes at us in the cyber-domain doesn’t mean we have to respond in the cyber domain.
"We think it’s important that potential adversaries out there know that this is part of our strategy."
Following last year’s attack on Sony Pictures Entertainment, the film subsidiary of the Japanese electronics conglomerate, the US arranged economic sanctions against North Korea, which it blamed for the hack.
According to the newswire Agence France-Presse, Rogers cited this as an example of non-cyber responses to online violence, and did not rule out physical weapons as another tool that could be used.
"It’s situational dependent," he said. "What you would recommend in one scenario is not what you would recommend in another."
Tensions between the US and its global rivals Russia and China have increased over the past few years, with both the latter countries accused of funding cyberattacks against Western companies and citizens.
The low costs of entry for cyber-weapons has also meant that poor countries like North Korea can fight on more equal terms with superpowers, whilst difficulty attributing attacks makes military deterrence more complicated.
Despite its complaints the US is widely believed to have developed the most potent cyber-weapon in history in the form of Stuxnet, a virus that attacked Iranian nuclear infrastructure over several years.