Reuters reporting the S.Korean met agency

  • S Korea intelligence agency says its possible that N Korea did not test a hydrogen bomb

The plot thickens.

S Korean president Park says they will act decisively against any new provocations from N Korea

  • must take decisive measures inc international sanctions
  • must co-operate with international community to make N Korea pay the price
  • latest test could fundamentally change N Korea nuclear issue

Meanwhile UK foreign sec Phillip Hammond has condemned the test if indeed it has been carried out

" If North Korean H-bomb test reports are true its is a grave breach of UNSC resolutions and a provocation which I condemn without reservation"

Update: 05.35 GMT -

  • S Korean intelligence agency says N Korea nuclear device explosion recorded at 6.0 kilotonnes
  • S Korean defence min says a small amount of hydrogen may have been added to N Korea nuclear test device