They didn't specify what they meant by citadels, but added: "The army and people of the DPRK are fully ready to stand in confrontation with the U.S. in all war spaces including cyber warfare space to blow up those citadels."
The statement — issued by the policy department of the North's National Defense Commission — is the latest salvo in the war of words over the massive hacking of Sony Pictures, which canceled the Christmas Day release of the film after hackers threatened theaters planning to show it.
The FBI has blamed the North Korean government for the hack attack, saying technical analysis had revealed links to North Korean-developed malware, including lines of code and encryption algorithms. A host of voices in the U.S., from Hollywood celebrities like George Clooney to President Barack Obama, have said Sony shouldn't have called off the release of the Seth Rogen-James Franco comedy about a plot to kill the North Korean dictator, and some lawmakers are saying the U.S. should put Pyongyang back on its list of state sponsors of terror.
North Korea has denied carrying out the cyberattack against Sony, and on Saturday, via KCNA, proposed a joint investigation with the U.S.
But they didn't make the same offer on Sunday. Instead, the policy department statement said North Korea had "clear evidence that the U.S. administration was deeply involved in the making of such (a) dishonest, reactionary movie." That included, the group said, a U.S. special human rights envoy "urging the movie makers to keep all scenes insulting the dignity of the DPRK (North Korean) supreme leadership in the movie, saying it is needed to 'vex the North Korean government.'"
The department also said it "highly estimates the righteous action taken by the 'guardians of peace'" — a reference to the self-professed hackers — but said it was not "aware of their residence." The White House declined to comment on the latest North Korean remarks.
NBC News Kristen Welker contributed to this report.