FILE - In this April 13, 2017 file photo, North Korean leader Kim Jong Un, center, arrives for the official opening of the Ryomyong residential area, in Pyongyang, North Korea. South Korea's military says North Korea is believed to have conducted its sixth nuclear test. South Korea's military said Sunday, Sept. 3, 2017, that North Korea is believed to have conducted its sixth nuclear test after it detected a strong earthquake, hours after Pyongyang claimed that its leader has inspected a hydrogen bomb meant for a new intercontinental ballistic missile. (ANSA/AP Photo/Wong Maye-E, File) [CopyrightNotice: Copyright 2017 The Associated Press. All rights reserved.]