Seoul's presidential spokesman Yoon Young-chan said Sunday Kim made the comments during his summit with South Korean President Moon Jae-in on Friday.
Yoon says Kim also said President Donald Trump will learn he's "not a person" to fire missiles toward the United States. The Kim-Trump meeting is anticipated in May or June.
Yoon says North Korea also plans to re-adjust its current time zone to match the South's. The North in 2015 created its own "Pyongyang Time" by setting the clock 30 minutes behind the South.