North Korea on Wednesday appeared to rule out any resumption of dialogue with the United States, threatening to react to any US "war of aggression" with nuclear strikes and cyber warfare.

The statement from the country's top military body, the National Defence Commission (NDC), came after reported moves by Washington and Pyongyang to revive long-stalled six-nation talks on denuclearisation.

The NDC said recent comments from President Barack Obama had revealed that the United States' goal was to "bring down" North Korea.

The statement was an apparent reaction to an interview Obama gave on January 22 in which he spoke of the eventual collapse of the North Korean regime, calling it "the most isolated, the most sanctioned, the most cut-off nation on Earth".

North Korean leader Kim Jong-Un, who is head of the NDC, said on the weekend that Pyongyang refused to sit any longer at the table "with rabid dogs barking" about toppling its socialist system.

"Since the gangster-like US imperialists are blaring that they will 'bring down' the DPRK (North Korea)... the army and people of the DPRK cannot but officially notify the Obama administration... that the DPRK has neither need nor willingness to sit at negotiating table with the US any longer," the NDC said.

If the US ignites "a war of aggression" and unleashes a nuclear war, North Korea will "counter it through its own nuclear strikes", it said in a statement carried by the North's official Korean Central News Agency (KCNA).

"And if the former tries to bring down the latter through a cyber warfare, it will react to it with its own preeminent cyber warfare and will thus bring earlier the final ruin of the US," said the statement titled "US imperialists will face final doom".

- 'Talks about talks' -

The Washington Post reported on Monday that US and North Korean nuclear envoys had been secretly discussing the idea of "talks about talks", but had been unable to agree on practical arrangements.

US State Department spokeswoman Jen Psaki said in response that Washington's position had not changed and that it "continues to offer Pyongyang an improved bilateral relationship" provided it takes action on denuclearisation.

South Korea's Unification Ministry spokesman Lim Byeong-Cheol said Wednesday that, despite the stand-off between Pyongyang and Washington, Seoul would continue efforts to "build trust through dialogue and cooperation" and improve ties with the North.

North Korea carried out nuclear tests in 2006, 2009 and 2013.

The aim of the six-party talks is to persuade the North to scrap its nuclear weapons in return for aid and other incentives such as security guarantees and diplomatic normalisation.

David Straub, a former US negotiator with the North, was quoted by the Post as saying both sides have for decades wanted to talk to each other. The issue now was what they want to achieve.

"The North Koreans have made it clear publicly and privately that they are a nuclear weapons state and that they intend to be a nuclear weapons state forever," he told the Post.

Hong Hyun-Ik, senior researcher at the private Sejong Institute in Seoul, said the United States was "in need of a trouble-making North Korea" to rally support from its allies for its ultimate strategy of keeping China's growing influence in check in the region.

"As its economy is currently in a better shape than the past, North Korea feels no sense of urgency resuming denuclearisation talks," Hong told AFP.

"Against this backdrop, neither North Korea nor the United States wants to take the initiative for a breakthrough."