North Korea appears to be laying the groundwork for a fifth nuclear test ahead of next month's ruling party congress, the first to be held in more than 30 years, a media report said Sunday, citing South Korean government sources.
The sources said South Korea had recently detected sharply increased vehicle and human activity at the North's Punggye-ri nuclear test site, according to the Yonhap news agency report.
"Compared to last month, the frequency of vehicle, workforce and equipment movements increased two- to threefold recently," the report cited multiple government sources as saying.