North Korea appears to have conducted an experiment with a detonation device in preparation for its seventh nuclear test, South Korea's deputy national security adviser Kim Tae-hyo said on Wednesday.
Kim also told a media briefing the North's missile test earlier in the day seemed to have involved its newly-developed Hwasong-17 intercontinental ballistic missile (ICBM).
(Reporting by Hyonhee Shin and Soo-hyang Choi; Editing by Jacqueline Wong)
