Kim Jong-un has told President Donald Trump he believes their efforts could open up a "new future" between North Korea and the US and expressed hope for "practical actions" in the future, according to a letter from the North Korean leader.
But Mr Kim, in the note posted by Mr Trump on Twitter, made no mention of any work by North Korea toward denuclearisation at a time when there has been no sign of concrete action by Pyongyang since the two leaders held a landmark summit in Singapore on June 12.
Despite that, Mr Trump hailed the July 6 letter as a "very nice note," saying "Great progress being made."
Mr Kim praised Mr Trump for "energetic and extraordinary efforts made by Your Excellency Mr. President for the improvement of relations between the two countries and the faithful implementation of the joint statement."
He was referring the summit statement signed by the two leaders in which Mr Kim agreed in broad terms to "work toward denuclearisation".
Mr Trump later said North Korea was no longer a nuclear threat, even though no details were announced, and critics suggested the president had failed to secure any new commitments from Pyongyang toward the dismantling of its nuclear missile program.
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The date of the letter suggests it may have been sent before Secretary of State Michael Pompeo's visit to Pyongyang last week, in which the United States and North Korea struggled to make headway on the denuclearisation issue.
North Korea accused the United States on Saturday of making "gangster-like" demands in the talks in North Korea, contradicting Pompeo who said the old enemies had made progress.
But Mr Kim's note, which Mr Trump included in his Twitter post with an image of the letter in Korean and an English-language translation of it, took a different tone.
"I firmly believe that the strong will, sincere efforts and unique approach of myself and Your Excellency Mr. President aimed at opening up a new future between the DPRK and the U.S. will surely come to fruition," he wrote, referring to North Korea by its acronym.