He continued to note that the USA has no current plans to relax sanctions on North Korea until there is evidence the country is taking steps to denuclearize, saying the Trump administration would continue its campaign of "maximum pressure".
North Korea said it has halted nuclear and missile tests and dismantled its nuclear test site as practical steps toward denuclearization, but it lashed out at the USA for unilaterally demanding North Korea denuclearize first.
North Korea's nuclear weapons program has caused global tension for decades and the rhetoric and threats from Kim and Trump had been especially hostile before their June meeting.
Still, North Korea said it remains steadfast in its commitment to building trust and implementing in good faith the joint statement step by step.
The stark comments come after Trump and Kim's June meeting in Singapore, during which the White House said the North had made firm pledges to rid itself of its nuclear weapons.
The unidentified spokesperson also warned that there is no guarantee that the hard-won atmosphere of stability on the Korean Peninsula will continue. Some experts say that North Korea does not want to denuclearize first or maybe denuclearize at all because it wants a long, drawn-out process that sees external aid shipped in in return for abandoning nuclear weapons. Among the agreements was holding another inter-Korean summit in the fall in Pyongyang. "What we need is performance from North Korea on denuclearization".
The foreign ministry said that despite their efforts to work with the US - by stopping their missile launches and nuclear tests - America continues to insist on "denuclearization first", and continues to encourage worldwide sanctions against the North.
Seoul said it accepted the North's proposal after Pyongyang first suggested a meeting Monday to discuss another summit between the leaders.
The president has also repeatedly defended Kim's intentions, tweeting last month that he was "confident" the leader would "honor the contract we signed &, even more importantly, our handshake".
North Korea nevertheless went ahead with the return of the remains of US soldiers killed in the 1950-53 Korean war, it said.
It has urged Washington to take reciprocal steps including officially declaring an end to the war and dropping sanctions. Russian Federation and China have suggested the U.N. Security Council could discuss loosening sanctions on Pyongyang after the June 12 Singapore meeting between Trump and Kim.
The Korean Peninsula is still technically in a state of war because the 1950-53 fighting ended with a ceasefire, not a peace treaty.