"The whole territory of the U.S.is within the range of our nuclear strike and a nuclear button is always on the desk of my office and this is just a reality, not a threat", he said, while emphasising that the weapons would only be used if North Korea is threatened.
Professor Kim Hyun-Wook at the Korea National Diplomatic Academy said the North was trying to use the Olympics to improve ties with the South despite tensions with the USA showing no signs of abating. North Korea's adoption of a proactive attitude on participating in the Pyeongchang Winter Olympics and a stern stance toward the USA must be seen as a desire to use inter-Korean dialogue as a key to open the door to dialogue with the hardline Trump administration.
But he also struck a conciliatory note, opening the door to dialogue with South Korea and saying he would consider sending a delegation to the Winter Olympics to be held in his southern neighbor in February.
But the North Korean leader said he would not use the weapons unless threatened. He also proposed last month that Seoul and Washington postpone annual joint military drills until after the Olympics, and he generally takes a less confrontational approach to relations with the North than his predecessor, Park Geun-hye.
Kim said in his televised New Year's address that the two Koreas should have "immediate talks" on the matter, Yonhap reported.
Kim said it is imperative to lower military tensions on the Korean peninsula and improve ties with the South, adding the path to dialogue was open. This is the role that Seoul can play in making progress in inter-Korean relations, easing tensions on the Korean Peninsula and laying the foundation for denuclearization talks between the USA and North Korea.
John Delury, a professor of worldwide relations at Yonsei University in Seoul, said Kim's message to Seoul was "more promising" than he had anticipated, addressing in a specific and actionable way South Korea's desire to make the Games a success.
They could, however, still take part via an invitation from the International Olympic Committee. "We are willing to talk with North Korea on the peaceful resolution of the North's nuclear program regardless of form, time and method", said Choi in a regular briefing.
North Korea conducted its sixth and most powerful nuclear test in September and launched its most high-tech intercontinental ballistic missile in November, ignoring global condemnation and steadily tightening sanctions. We welcome the fact that North Korea strongly hinted at its willingness to improve inter-Korean relations in the New Year.
"I regret the government had even lost the flexibility to spend one day or two taking a deep breath and meticulously analysing Kim Jong Un's ulterior motive before hastily issuing a welcoming statement", he said.
After North Korea tested its most powerful intercontinental ballistic missile (ICBM) in November, which it said was capable of delivering a warhead to anywhere in the United States, Kim declared his nuclear force complete.