The test shot, the 12th this year, began on the eve of the annual joint US-South Korean military exercises. Pyongyang has denounced the nine-day exercise as an invasion attempt. The United States has already conducted naval exercises with Japanese forces in the Sea of Japan, which the North said was a challenge. The deliberate timed launch follows others that included the first test flight of an intercontinental ballistic missile in five years. There are concerns that North Korea may be planning another nuclear test explosion. The last one, on September 3, 2017, had a yield that is estimated to be between 100