Ukrainian President Volodymyr Zelenskyy broke a confidentiality agreement by disclosing publicly that Kyiv had sent North Korean prisoners of war to South Korea, the East Asian country's president said Thursday.

The remarks by President Lee Jae Myung came after Zelenskyy told the United Nations that two North Korean soldiers had been recently sent to South Korea after being captured while fighting for Russia in the war against ​Ukraine.

"These ⁠guys are not easy to capture alive. One of them, when he realized he was going to be taken prisoner, tried to kill himself. And he was shocked that fate did not let him die," Zelenskyy said in his speech.

Ukraine captured the two North Koreans in Russia's Kursk region in January 2025. They were the first North Korean soldiers to be captured alive since the country joined the Russia-Ukraine war in 2024.

Zelenskyy said at the time that he would hand them over to North Korean leader Kim Jong Un if he could facilitate their exchange for Ukrainians held captive in Russia.

Human rights groups, however, urged him to send them to South Korea, citing the risks of punishment the soldiers faced. South Korean media reported that the two captured soldiers had expressed their desire to ⁠defect ⁠to South Korea.

The revelation prompted South Korea's political opposition to criticize the Lee administration for allowing a foreign leader to inform them of the prisoners' arrivals.

South Korean president said it was "deeply regretful" that Ukraine had made the transfer public, adding that the two sides had agreed not to disclose it.

"I do not know why the Ukrainian side broke the agreement and made the matter public, but it is very disappointing," Lee said on the social media platform X.

"The issue of bringing North Korean prisoners to South Korea is a highly sensitive one that could have a major impact on diplomacy, security and the situation on the Korean Peninsula," he said.

Lee said there had been calls to disclose the arrivals, but "given the problems that could arise from making it public, we agreed that keeping it confidential was the right thing to do."

Zelenskyy's aide Dmytro Lytvyn told journalists that Ukraine was "an open country" and that it would have been strange to hand over the soldiers in secret.

"From the entire story – which is long and detailed – we reported only the fact itself, that they were sent to the Republic of Korea," he said.

Timing of transfer

A South Korean lawmaker had previously said the pair wanted to live a "normal life" in the South.

Under South Korea's constitution, all Koreans, including those living in the North, are considered citizens, and officials have said this would apply to any North Korean troops captured in Ukraine.

The transfer comes as South Korea has voiced support for efforts to revive dialogue with North Korea and U.S. President Donald Trump has renewed his willingness to engage with Pyongyang.

Opposition politicians in South Korea questioned why Seoul had not announced the matter first.

South Korean opposition lawmaker Yu Yong-weon told ⁠reporters on Thursday that the two men had left Ukraine last weekend, transited through a third country and arrived in South Korea three to four days ago, Yonhap News Agency reported.

"While their exact location is unknown, I believe our intelligence agencies are protecting them," Yu ​was quoted as saying.

South Korea said in June it would accept any North Korean prisoners of war captured after fighting for Russia and ⁠opposed their repatriation to ‌either Russia ‌or North Korea.

In his address, Zelenskyy criticized North Korea's deployment of troops to ⁠support Moscow.

"This is madness too. Why should Koreans give their lives ‌in a war against Ukraine? Kim Jong Un uses them like currency. And he gets something in return," he said.

North Korea has sent ​an estimated 14,000-15,000 troops to support Russia's war ⁠since 2024, according to Ukrainian and South Korean estimates, with most deployed in the ⁠Kursk region to help repel a Ukrainian incursion.

Pyongyang has also supplied Russia with millions of artillery and mortar rounds, ⁠as well as ballistic ​missiles, long-range artillery systems and multiple-launch rocket systems, according to Ukrainian and independent assessments.