North Korea launched four more ballistic missiles on Sunday, according to Japanese Prime Minister Shinzo Abe.
A spokesman for the South Korea said "several projectiles" were launched, falling into Japan's exclusive economic zone after flying around 620 miles.
It was not immediately clear exactly what type of missile were fired, but it they be an upgraded prototype of an intercontinental ballistic missile.
Just days before President Donald Trump's inauguration, two North Korean missiles were placed on mobile launchers to possibly antagonize the incoming administration.
And last week, North Korean leader Kim Jong Un executed five senior officials from his Ministry of State Security with anti-aircraft guns -- punishments for unspecified "false reports" that "enraged" the dictator.
The totalitarian state has also refused of any wrongdoing in the apparent assassination of Kim Jong Un's half brother, Kim Jong Nam.