North Korea fired at least one unidentified projectile eastward, South Korean and Japanese authorities said on Saturday.
In Tokyo, the Japanese Ministry of Defence said the projectile appeared to have landed outside Japan's exclusive economic zone in the Sea of Japan.
According to South Korea's military Joint Chiefs of Staff (JCS) in Seoul said it detected the launch.
The report comes as South Korea and the United States are in the middle of their annual combined military drills, known as Freedom Shield.
Pyongyang has repeatedly condemned the allies' joint exercises as a rehearsal for an invasion.
The two allies, however, maintain that their manoeuvres are purely defensive in nature.
South Korean news agency Yonhap reported that Kim Yo Jong, the powerful sister of North Korea's leader Kim Jong Un, had condemned the ongoing military exercises and warned of "unimaginably terrible consequences."
North Korea last launched short-range ballistic missiles toward the East Sea, also known as the Sea of Japan, on January 27. The North Korean leadership at the time spoke of testing "a large-calibre multiple rocket launcher system upgraded with new technology."
North Korea is prohibited by UN resolutions from launching or even testing ballistic missiles of any range. These are usually surface-to-surface missiles that can be equipped with a nuclear warhead.
