The comments in state media yesterday came as the UN Security Council is due to meet next week to discuss North Korea's rights record, amid calls for Pyongyang to be referred to the international court for crimes against humanity.
But after CIA torture revelations last week, North Korea hit back, slamming the US for committing "the gravest human rights violations in the world" and carrying out "brutal medieval forms" of torture.
"The US will have to experience the toughest-ever counteraction against its hostile policy against the DPRK (North Korea)," he said, without elaborating.
North Korea has written to the Security Council requesting a commission be set up to investigate and prosecute those responsible for the CIA abuses.
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Its attempts at retaliation are part of an outraged response to a UN inquiry released in February that argued Pyongyang's rights violations pose a threat to international peace and security.
Separately, the North Korean spokesman also said the United States would bear responsiblity for "the breakdown of the denuclearisation of the Korean peninsula".
"As the United States adheres to its plot to overturn our system by every means available, the commitment to denuclearising the Korean peninsular will lose its meaning completely," he said.
"As the DPRK-US war over human rights is now underway, any dialogue on the nuclear issue losess all its meaning."
However, the US-Korea Institute at Johns Hopkins University said last week recent satellite images suggested North Korea was unlikely to follow through on a threatened nuclear test anytime soon.