South Korea’s presidential office has demanded an apology from Ukraine for denying an agreement to keep the transfer of two North Korean prisoners of war to Seoul confidential.

The incident came after Ukrainian President Volodymyr Zelenskyy told the United Nations that his country had sent two North Korean soldiers to the South, adding they were “not easy to capture alive”.

Hours later, South Korea’s President Lee Jae Myung said on X, “I do not know why the Ukrainian side broke the agreement and made the matter public, but it is very disappointing.”

As a response to this, Mr. 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.

“It is in itself a very serious matter that the Ukrainian side violated the confidentiality agreement between the two countries and made the disclosure unilaterally,” Seong Ghi-hong, senior presidential secretary for public relations, said in a statement late on Sunday.

“But the Ukrainian presidential press office’s false statement that there had been no confidentiality agreement… seriously undermines trust between the two governments and gravely damages friendly relations between the two countries,” he said.

The South Korean Presidential office demands “an official explanation and apology,” said Mr. Seong.

The South Korean presidential office is “considering additional measures that may be necessary regarding this matter,” he added, but did not specify what they were.

Early last year, Ukraine captured two North Korean soldiers among Pyongyang’s troops fighting for Moscow.

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.