North Korean leader Kim Jong Un on Thursday said Pyongyang had "already explored every possible avenue in negotiating with the U.S." and accused America of ramping up tension and provocations.
The comments come less than two months before President-elect Donald Trump takes office and amid international criticism over increasingly close military cooperation between Pyongyang and Moscow.
Previous negotiations with Washington have only highlighted its "aggressive and hostile" policy toward North Korea, Kim said in a speech at a military exhibition in Pyongyang, the capital, the KCNA news agency said.
"Never before have the warring parties on the Korean peninsula faced such a dangerous and acute confrontation that it could escalate into the most destructive thermonuclear war," he said on Thursday.
"We have already gone as far as we can on negotiating with the United States," he said, adding that the talks had only shown its aggressive and hostile policy toward North Korea could never change.
Trump, who held multiple face-to-face meetings with Jong Un during his first term, said while on the campaign trail this year that relations between the U.S. and North Korea would improve during his second term.
Information from Reuters was used in this report.