Departing from his usual black or navy suits, Kim gave his televised speech wearing black-rimmed glasses and slicked back hair, speaking fluently and rarely looking down to read as he raised the possibility of sending a delegation to the upcoming Winter Olympics in South Korea.
On Monday, North Korean leader Kim Jong-un delivered his 2018 New Year's Day address, as he has done every year since 2013. Analysts say Kim may be trying to drive a wedge between Seoul and its ally Washington as a way to ease worldwide isolation and sanctions against North Korea.
Moon's unification minister, Cho Myoung-gyon, proposed in a nationally televised news conference that the two Koreas meet January 9 at the shared border village of Panmunjom to discuss Olympic cooperation and how to improve overall ties.
Ship-to-ship trade with North Korea at sea is prohibited under United Nations sanctions adopted September 11.
Should the talks be held on January 9, it would be the first such dialogue since a vice-ministerial meeting in December 2015.
"As for the areas of nuclear weapons research and rocket engineering, we need to accelerate the mass production of nuclear warheads, whose power and reliability have already been secured, and ballistic missiles", Kim said, adding that the country also needed to be ready "to retaliate against the enemy's move for a nuclear war".
South Korea said Friday that in late November it had seized the Hong Kong-flagged Lighthouse Winmore, which is suspected of transferring as much as 600 tons of oil to the North Korea-flagged Sam Jong 2.
But Mullen also said that Trump has disrupted long-held views of the US role in the world, and that America's enemies benefit from that uncertainty.
Kim, who said on Monday that he always had a nuclear launch button on his desk, has presided over multiple missile tests in recent months and the North's sixth and most powerful nuclear test - which it said was a hydrogen bomb - in September.
Kim appeared to extend an olive branch to Seoul in his address to the nation today, saying the Olympics would "serve as a good chance to display our Korean people's grace toward the world and we sincerely hope the Games will be a success".
Past year was also notable for a war of words between Kim and Trump, who repeatedly threatened military action to stop the rogue state's nuclear program.
In his New Year's address, Kim again denounced the exercises.