Update at 1355 KST: This article has been amended to include an up to date statement by South Korea’s Joint Chiefs of Staff (JCS) 

Update at 1315 KST: This article has been amended to include an up to date assessment by USGS

A 6.3 magnitude seismic event, likely a nuclear test, was detected approximately 10 km from North Korea’s nuclear test site on Sunday afternoon, the United States Geological Survey (USGS) earthquake monitoring service indicated.

The event, which appears to be North Korea’s sixth ever nuclear test, has led South Korea’s National Security Council (NSC) to convene an urgent meeting,