President Lee Jae Myung is again finding social media spilling into a diplomatic dispute, this time with Ukraine, after a similar row with Israel in April, as he steps up his activity on X (formerly Twitter) to address sensitive foreign and domestic issues. Lee warned Ukraine on Friday that South Korea would take “additional measures” unless Kyiv acknowledges and issues a public apology over what Seoul says was an agreement to keep the transfer of two North Korean prisoners of war confidential. The disagreement began after Ukrainian President Volodymyr Zelenskyy disclosed in a U.N. General Assembly speech on Sept. 23 that the soldiers had been sent to South Korea. They were captured while fighting for Russia and later expressed a desire to resettle in the South. Seoul said the disclosure violated an arrangement intended to protect the men and their families. Ukraine denied that any such agreement existed and described the episode as a diplomatic misunderstanding. Lee initially wrote on X that Zelenskyy’s announcement was “very disappointing” and later escalated his criticism by