SEOUL—South Korean officials began preparations on Friday for a summit next month with North Korea aimed at reducing tensions on the peninsula, as a report showed the North had probably begun testing a nuclear reactor as recently as late February.
The report by intelligence analysts at Jane’s by IHS Markit said satellite imagery from Feb. 25 showed emissions of non-condensable gases from a stack at the North’s experimental light water reactor (ELWR) at the Yongbyon Atomic Energy Research Center, suggesting preliminary testing had likely begun.
