South Korea's intelligence service has assessed that Volodymyr Zelenskyy's disclosure of a transfer involving two North Korean prisoners of war was likely intended to build public support in South Korea for greater assistance to Ukraine, according to lawmakers who attended a closed parliamentary briefing.

The disclosure, made during Zelenskyy's United Nations speech last week, surprised officials in Seoul. South Korea said it had expected the transfer to remain confidential and asked Kyiv for an explanation and an apology; Ukraine has denied agreeing to any nondisclosure arrangement.

The two soldiers were among North Koreans sent to Russia's Kursk border region as military cooperation between Moscow and Pyongyang expanded, AP reported. South Korea's intelligence service says the men arrived in the South in mid-September and had expressed a wish to resettle there while in Ukraine.

The agency's assessment of Kyiv's motive is an intelligence judgement, not a proven fact. It comes in a policy context where South Korea has provided humanitarian and other support to Ukraine but has not supplied weapons to a country engaged in an active conflict.

The episode tests an otherwise close Kyiv-Seoul relationship at a sensitive moment. It also shows how North Korea's direct involvement alongside Russia can draw the Korean Peninsula further into the diplomatic politics of the Ukraine war, even where the immediate issue is the treatment and public disclosure of two prisoners.