North Korea unsuccessfully fired an intercontinental ballistic missile during a new salvo of launches Thursday, the South Korean military said.
The launches prompted South Korea and the United States to extend their ongoing joint air drills, the largest-ever such exercises, citing North Korea's "provocations".
People in parts of northern Japan were ordered to seek shelter during the North's latest launches, which included two short-range missiles and followed a blitz of projectiles fired Wednesday.
The largest of Thursday's launches, however, "is presumed to have ended in failure", the South Korean military said.
Seoul's Joint Chiefs of Staff said the ICBM appeared to have failed during "second-stage separation".
"The range of the long-range ballistic missile is around 760 kilometers, altitude of 1,920 kilometers at speed of Mach 15," the military said.
It also detected what were "believed to be two short-range ballistic missiles fired at around 08:39 am from Kaechon, South Pyongan province."
The United States condemned the ICBM launch despite its apparent failure.
"This action underscores the need for all countries to fully implement DPRK-related UN Security Council resolutions," US State Department spokesman Ned Price said, using the North's official name of the Democratic People's Republic of Korea.
Washington also confirmed information provided by the South Korean military, which said earlier it had detected the launch of the long-range ballistic missile at around 7:40 am (2240 GMT Wednesday) in the Sunan area of Pyongyang.
