The missiles were in response to North Korea launching a ballistic missile over Japan on Tuesday. This first launch of a North Korean medium-range missile over Japan since 2017 had triggered international outrage. According to Seoul, the rocket traveled about 4,500 kilometers, which could mean a new record for North Korea.

The government in Tokyo had called on its citizens in two northern regions to seek shelter in buildings or basements. The United States and Japan said the North Korean missile launch not only posed a threat to the Japanese people, but also “destabilized the region.”

The United States and South Korea had also responded with a military exercise in which satellite-guided precision bombs were fired at a virtual target in the West Sea, the General Staff in Seoul announced. Four South Korean F-15K fighter jets and F-16 machines from the US Air Force were used in the exercise.

Washington and Seoul are close allies. Around 28,500 US soldiers are stationed in South Korea.

North Korea has fired ballistic missiles four times in the past few days. South Korea and the United States fear that North Korea could conduct a nuclear weapons test again in the near future for the first time since 2017. The largely isolated Asian country has tested nuclear weapons six times since 2006, most recently in 2017. According to diplomats, however, North Korea has not yet managed to combine its nuclear bombs and ballistic missiles into a unified system.