North Korea has carried out its biggest nuclear-test yet. South Korean officials say it may have been twice as powerful as previous detonations, causing a 5.3 magnitude seismic event at the north main test site.

朝鲜进行了迄今为止最大规模的核试验。韩国官员表示，其强度是此前爆炸的两倍, 造成北部主要试验区5.3级地震。