TEHRAN, Young Journalists Club (YJC) - But he also struck a conciliatory tone in his New Year's address, wishing success for the Winter Olympics set to begin in South Korea in February and suggesting the North may send a delegation to participate.
Kim, wearing a Western-style gray suit and tie, said in his customary annual address that his country had achieved the historic feat of "completing" its nuclear forces and added that he has a nuclear button on his desk.
"The U.S. should know that the button for nuclear weapons is on my table," he said during the speech, as translated by The Associated Press.
"The entire area of the U.S. mainland is within our nuclear strike range. ... The United States can never start a war against me and our country," Kim said.
He also called for improved relations with the South, an idea mentioned in speeches more often than it is met.
He said the Pyeongchang Winter Olympics would be a good opportunity to showcase the status of the Korean nation.
He also said the two Koreas could meet urgently to discuss the North sending a delegation.
"The Winter Olympic games that will be held soon in the South will be a good opportunity to display the status of the Korean nation and we sincerely wish that the event will be held with good results," he said.
South Korea's presidential office said it welcomed the proposal to hold talks between government officials over the issue of North Korea sending a delegation to the Olympics.
The office of President Moon Jae-in said the successful hosting of the Pyeongchang Olympics would contribute to peace and harmony not only on the Korean Peninsula and in Northeast Asia, but in the entire world.
The New Year's address is an annual event in North Korea and is watched closely for indications of the direction and priorities Kim may adopt in the year ahead.
This year's speech was seen as particularly important because of the high tensions over Pyongyang's frequent missile launches and its nuclear test in 2017.
Kim also stressed North Korea's economic achievements during the speech, and noted the importance of improving the nation's standard of living.