South Korean Unification Minister Jung Dong-young poses at the Joint Security Area in the Demilitarized Zone, July 25, 2025. (Brendan Trembath/U.N. Command)
A dispute in South Korea’s capital over a government minister publicly disclosing the site where North Korea enriches uranium for nuclear weapons is rippling across the U.S. alliance, according to government sources.
South Korea’s Defense Intelligence Agency on Tuesday alleged that the country’s unification minister may have revealed classified information when he spoke publicly about North Korea’s Kusong region, the nuclear site, a spokesman for National Assembly Rep. Lim Jong-deuk said by phone Thursday.
Unification Minister Jung Dong-young identified the site during a National Assembly committee meeting on March 6, according to a YouTube video of the meeting.
The intelligence service notified Lim Jong-deuk, a member of the National Defense Committee, that information about the facility “is classified as South Korea-U.S.’s joint secret, therefore public disclosure is limited,” according to Lim’s spokesman, who declined further comment.
Some South Korean government officials must speak to the media on condition of anonymity.
Rep. Sung Il-jong, chair of the National Defense Committee at the National Assembly, told reporters on Tuesday that Jung’s remarks have created a rift in the U.S.-South Korean alliance, according to a YouTube video of the briefing.
Sung said U.S. Army Gen. Xavier Brunson, commander of U.S. Forces Korea, had met with South Korean National Defense Minister Ahn Gyu-back to protest the alleged disclosure.
A spokesman for Sung’s office declined by phone Wednesday to provide additional details.
The National Defense Ministry on Tuesday denied Sung’s account.
Sung’s statements about Brunson are “not true at all,” and for the USFK commander to raise such a protest in the context of alliance diplomacy would be inappropriate, said a text message to reporters from a ministry spokesperson.
USFK spokesman Kim Eun-chong also declined comment on by email Thursday, saying the command has “nothing to add.”
South Korean President Lee Jae-myung defended Jung in a post Monday on X, saying knowledge of the North Korean facility was already in the public domain.
Lee wrote that the facility’s existence was widely known and had appeared in media reports even before Jung’s remarks.
He dismissed claims of a leak as “false” and called for an investigation into the controversy.
The Unification Ministry’s deputy spokesman, Yoon Min-ho, echoed that stance during a general briefing on Monday, saying Jung’s comments were based on public knowledge, according to a briefing transcript.
He said Jung made similar remarks during his ministerial confirmation hearing in July.
South Korean media on Tuesday, citing unnamed military officials, reported the U.S. has partially limited South Korea’s access to intelligence on North Korean technology collected via satellites in the wake of Jung’s remarks.
However, the defense ministry’s message said the allies remain “in close communication and are maintaining a close intelligence sharing system, including monitoring North Korea’s missile launch activities.”
Seoul and Washington are “in constant communication on major matters and strictly adhere to the General Security of Military Information Agreement,” the message said.
Kim said USFK works alongside its South Korean ally “every day to deter aggression and maintain peace and stability on the peninsula,” but declined to comment on reports about limits on intelligence access.
