U.S. official links S. Korea's watchlist status to lab data misstep

The U.S. Department of Energy put South Korea on a watchlist because visitors to its laboratories mishandled sensitive information, Joseph Yun, the acting U.S. ambassador to South Korea, said on Tuesday.

The designation, which relegated the U.S. ally to the lowest tier of a list, sparked controversy and debate in Seoul, which said it had not been notified by Washington.

"South Korea was put on this list because there was some mishandling of sensitive information," Yun said in remarks to the American Chamber of Commerce in Korea.

He did not elaborate on the issue but said more than 2,000 South Korean students, researchers, and government officials visited U.S. labs last year.

Yun said that the designation was limited to the department's facilities and did not have wider implications for cooperation between the allies.

"It is not a big deal," he added. "There were some incidents because there were so many South Koreans going there."

This week, the U.S. Department of Energy confirmed that it had designated South Korea a "sensitive" country in January but did not explain why.