A 5.1 magnitude tremor has been felt close to North Korea's nuclear test site, triggering concerns that Pyongyang has carried out an atomic explosion. South Korea's Met Agency said it was "highly likely" a nuclear test.
The earthquake was registered by the China Earthquake Network Center at 9:30 a.m. Beijing time (0130 UTC) on Wednesday.
According to the US Geological Survey, the epicenter of the quake was in the northeast of North Korea, some 50 kilometers (30 miles) northwest of Kilju city. If correct, the epicenter would have been directly next to the Punggye-ri nuclear test site.
South Korea's Yonhap news agency said ministers were holding an emergency meeting.
"We suspect a man-made earthquake and are analyzing the scale and epicenter of the quake with the geo-science and mineral resource institute of South Korea," a Korea Meteorological Administration official told Reuters news agency.
North Korea has conducted three nuclear tests in the last 10 years, the most recent of which was in February 2013. If confirmed, the test would raise fears that Pyongyang is persevering in its efforts to build a warhead, small enough to be mounted on a missile and capable of reaching the shores of mainland America.
ksb/rc (Reuters, AFP, AP)