Neighbors of North Korea condemned what it said was its first test of a hydrogen bomb on Wednesday, calling the development a threat to the region’s stability and a violation of United Nations resolutions banning nuclear arms tests by the North. In Seoul, President Park Geun-hye convened an urgent meeting of her top national security aides. As South Korea’s military increased its vigilance along the heavily militarized border with the North, its diplomats rushed to discuss with allies what Ms. Park called “strong sanctions” against Pyongyang. Read more
