TOPSHOT - ADDITION-
People watch a news report on North Korea's first hydrogen bomb test at a railroad station in Seoul on January 6, 2016. South Korea 'strongly' condemned North Korea's shock hydrogen bomb test and vowed to take 'all necessary measures' to penalise its nuclear-armed neighbour.  The image shown on TV shows files images from other nuclear tests from other countries and the caption in red at the bottom of the screen reads 'the Blue House will convene an emergency meeting of the NSC, the National Security Council.'   AFP PHOTO / JUNG YEON-JE / AFP / JUNG YEON-JE        (Photo credit should read JUNG YEON-JE/AFP/Getty Images)