According to state-run television, North Korea has tested a nuclear warhead designed to be mounted on a ballistic missile.
The test is North Korea's second nuclear test this year, and is being condemned by world leaders. It comes despite sanctions imposed by the West that are supposed to hinder North Korea's nuclear program.
Here & Now's Robin Young hears the latest from the BBC's Steve Evans in Seoul.
Steve Evans, BBC correspondent in Seoul. He tweets @EvanstheAirwave.
This segment aired on September 9, 2016. The audio for this segment is not available.