North Korea fired a ballistic missile on Saturday, South Korea's military said, three days before the inauguration of South Korean president-elect Yoon Suk-yeol, who has vowed to take a hard line against the North.
South Korean military said that North Korea fired what is believed to be an submarine-launched ballistic missile (SLBM).
The launch took place near North Korea east coast around Sinpo, where North Korea keeps submarines as well as equipment for test-firing SLBMs.
Japan's Defense Ministry also confirmed that the projectile could be a ballistic missile. A Japanese public broadcaster, citing government sources, said the projectile landed outside Japan's exclusive economic zone.
The last launch of a ballistic missile by the North Korea took place on Wednesday. Pyongyang vowed to develop its nuclear forces "at the fastest possible speed".
The United States assessed that North Korea was preparing its Punggye-ri nuclear test site and could be ready to conduct a test there as early as this month. If it happens, that would be the first test since September 2017 and a seventh nuclear test in general.
In March, Kim Jong Un personally led tests of North Korea's largest intercontinental ballistic missile in history. By that he demonstrated that his country was ready for a "long-term confrontation" with the United States.