The U.S. Geological Survey says a 6.3-magnitude “explosion” was detected in North Korea on Sunday.
“Possible explosion, located near the site where North Korea has detonated nuclear explosions in the past,” says a statement on the USGS website. “If this event was an explosion, the USGS National Earthquake Information Center cannot determine its type, whether nuclear or any other possible type.”
It was recorded near Punggye-ri, a nuclear test site, near the border with China in the country’s northeastern region.
The USGS says the seismic activity was not identified as a natural earthquake, meaning that Pyongyang may have tested another nuclear device.
It comes hours after leader Kim Jong Un inspected an alleged hydrogen bomb being placed on an intercontinental ballistic missile.
South Korea’s Meteorological Administration described it as a “man-made” earthquake.
South Korea’s Joint Chiefs of Staff say North Korea is “presumed” to have carried out another nuclear test, South Korea’s official Yonhap News Agency reported on Sunday.
According to Yonhap, “All South Korean troops have been put on high alert. South Korea’s presidential office Cheong Wa Dae immediately convened a National Security Council meeting on the issue.”
“An artificial earthquake movement of 5.6 Richter scale has been suspected near Poonggaeri area in North Kroea at around 12:34 pm KST and we are conducting further analysis about the nature of this artificial earthquake,” a South Korean military official was quoted by NBC News as saying.
South Korean leaders will hold a National Security Council meeting on Sunday, a presidential spokesperson told NBC.
China’s earthquake administration told Reuters that the quake is a “suspected explosion.”
North Korea tested two nuclear weapons last year.
Since 2006, five tests have been carried out in all.