He said Monday: "It was a different world. That was a dangerous time. This is one year later, a much different time."
US President Donald Trump says the second summit with North Korean leader Kim Jong Un is likely to take place "quite soon."
Speaking at the United Nations, Trump says the relationship with the country whose leader he branded last year as "Little Rocket Man" is much improved.
"It was a different world. That was a dangerous time. This is one year later, a much different time," he said.
Trump says Secretary of State Mike Pompeo is working out the details for the second Trump-Kim meeting.
Kim requested a second meeting with Trump in a letter this month, and Trump says, "we will be doing that."
Trump is set to meet with South Korea's Moon Jae-in to discuss North Korea and trade details. Moon is expected to convey to Trump a personal message from Kim delivered at their inter-Korean talks last week.
Trump is at the United Nations for his second general assembly meeting with world leaders since taking office and has participated in a counter-narcotics event.