Nuclear envoys from South Korean and China met in Beijing to share concerns about nuclear security in the Korean Peninsula.
A South Korean diplomat told the Yonhap News Agency on condition of anonymity that both sides were keeping close watch on recent developments in the North Korean nuclear sector.
Satellite imagery of North Korea reviewed last month by IHS Jane's Defense Weekly suggested Pyongyang made good progress on the construction of a light-water uranium reactor.
"Both sides don't see any serious situations with regard to the reactor," the envoy said on condition of anonymity.
Enriched uranium could find its way into the North Korea nuclear arsenal. The country's first nuclear tests in 2006 and 2009 were believed to have used plutonium devices.
A recent report by the Bulletin of the Atomic Scientists stated a tunnel completed near the site of the country's first two nuclear tests suggests North Korea might be capable of another nuclear test soon.
The envoy told Yonhap, however, that Beijing and Seoul saw "no immediate sign" that North Korea was preparing for a third nuclear test.