Pentagon takes computer system offline after detecting suspicious activity

Officials will not say exactly what happened, but the US military’s Cyber Command is now investigating the matter according to Lieutenant Colonel Valerie Henderson, a Pentagon spokesman.

So far, there is no indication any classified systems were impacted, officials said.

Dempsey and other critical senior personnel have been provided “a work around” so they can access their unclassified email, a defence official said.

Right now the focus is on “mitigating the cyber security risks we see across our impacted network,” the official said.

The report comes days after the FBI said the US has witnessed a 53 per cent spike in economic espionage cases aimed at American firms, with a vast majority of the perpetrators originating from China with ties to the government.

The head of the Federal Bureau of Investigation’s counterintelligence division, Randall Coleman, said there has been a 53 per cent increase in economic espionage cases, or the theft of trade secrets leading to the loss of hundreds of billions of dollars, over the past year.

Coleman said that state-sanctioned corporate theft by China is at the core of the problem. China has in the past denied any involvement in hacking into foreign computer systems.

He cited examples of large corporations successfully targeted in the past such as DuPont, Lockheed Martin and Valspar, who have since worked with the FBI to further safeguard their intellectual property.