The US has partly restricted intelligence sharing with South Korea after the country’s unification minister publicly identified a suspected North Korean nuclear site, according to reports in South Korean media.
Chung Dong-young told lawmakers in March that North Korea was operating uranium enrichment facilities in Kusong, a north-western area that had not previously been officially confirmed as a nuclear site alongside the known facilities at Yongbyon and Kangson.
A senior military official told the state-funded Yonhap news agency on Tuesday that Washington had imposed partial restrictions on sharing satellite-gathered intelligence about North Korean technology since early this month, though surveillance of missile activity continued normally and military readiness remained unaffected.
The restrictions followed what South Korean outlets described as multiple protests from US officials, who expressed concern that sensitive information had been disclosed without authorisation.
No US agency has confirmed the restrictions on record. The Guardian contacted the US embassy in Seoul for comment.
Chung has defended his remarks, saying they were based on publicly available research rather than classified intelligence.
He told reporters on Monday it was “deeply regrettable” that his policy explanation had been characterised as an information leak. “This is open information,” Chung said, citing a 2016 report by a US thinktank and South Korean media coverage.
He noted he had mentioned Kusong during his confirmation hearing last year without incident. Writing on Facebook, he said he was “bewildered” the issue had suddenly become a problem nine months later.
President Lee Jae Myung, whose administration is pursuing a conciliatory approach towards North Korea, backed his minister. Writing on X, Lee said it was a “clear fact” that Kusong’s existence had been widely reported in academic papers and media before Chung’s remarks.
“Any claims or actions premised on the assumption that minister Chung leaked classified information provided by the United States are wrong,” Lee wrote from Delhi during a state visit to India. “I must look closely into why such an absurd situation is unfolding.”
The restrictions come amid broader tensions in the alliance, according to South Korean media reports.
The progressive newspaper Hankyoreh reported that Washington had cited several grievances when notifying Seoul of the measures, including pending legislation that would grant Seoul authority over access to the demilitarised zone, an area currently managed exclusively by the US-led UN command.
Conservative opposition politicians have called for Chung’s dismissal, describing his remarks as damaging to the alliance with Washington. In a statement, the People Power party called it a “clear security disaster”.
The unification ministry maintains it had sufficiently explained the basis for Chung’s remarks to the US and that no classified information was involved.
South Korea’s defence ministry declined to specify details about intelligence sharing arrangements but said close cooperation with the US continued.
The 2016 report Chung later cited in his defence, by the Institute for Science and International Security, identified a suspected early centrifuge research facility near Panghyon air base in the Kusong area but described it as a “preliminary site identification” requiring further confirmation.
North Korea is believed to have significantly expanded its nuclear programme in recent years.
Rafael Grossi, the head of the International Atomic Energy Agency, said during a visit to Seoul last week that the agency had confirmed “a rapid increase in the operations” of the Yongbyon reactor.
“All that points to a very serious increase in the capabilities of the DPRK in the area of nuclear weapons production, which is estimated at a few dozen warheads,” Grossi told reporters.