Washington (CNN) A top U.S. official on Thursday called the recent hack of Sony by North Korea a ground-breaking event in cyberwarfare and outlined the role of the National Security Agency in the investigation.

The head of U.S. Cyber Command, Admiral Mike Rogers, speaking at the International Cyber Security Conference in New York City hosted by Fordham University, said the U.S., for the first time, was the victim of a "malicious act by a nation-state specifically designed to achieve a coercive effect" in the cyber-arena.

Rogers said in this case the act came in the form of an effort to "stop the release of a film with a particular viewpoint and the characterization of a leader," in reference to the recent hacking of Sony by North Korea.

He said the NSA's role in the investigation as "providing technical assistance," which included investigating the malware used in the hack, as well as the data generated from Sony to compare with other hacking activity.

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