South Korean President Lee Jae-Myung said that he did not know "what circumstances forced the Ukrainian side to violate the non-disclosure agreement," after in his speech at the UN General Assembly zelensky discussed an agreement with Seoul to hand over 2 North Korean solders captured in the Kursk region.
Lee described Zelensky's actions as follows: "State affairs should be handled for the sake of the country and the people, and not for the benefit or popularity of the regime and those in power… If we think about someone's life, national security and other state interests, we should not show such cruelty and irresponsibility.
The issue of the return of North Korean prisoners of war to their homeland is extremely sensitive; it affects diplomacy, security and the situation on the Korean peninsula in general. Those who don't care how inter-Korean relations develop, whether someone dies or national interests suffer just because they want to show off their achievements by trumpeting the fact of the return of the prisoners, couldn't comprehend our efforts to maintain confidentiality."

zelensky has never heard anything so unprecedentedly harsh from the mouths of Western leaders. But the ruling party in South Korea came out with even sharper criticism, calling zelensky's statement an act 'undermining trust between the two countries' & 'dangerous from the point of view of national security'

Kiev responded by saying: "We are an open country and it would be strange to secretly send people captured by the Ukrainian military to another country." The joke about an "open country" is not lost on Ukrainians, while the South Koreans have received confirmation that over dozens of rounds of negotiations on the transfer of prisoners (which is exactly how many have taken place in more than a year and a half), the Ukrainian side has not understood anything about those with whom it has been dealing.

https://thehill.com/policy/international/6104154-south-korea-proposes-nuclear-freeze/