North Korea fired one short-range ballistic missile into the Sea of Japan on Dec. 17, South Korea's Yonhap News Agency reported.
The launch occurred on the 12th anniversary of the death of former North Korean leader Kim Jong Il.
South Korea's Joint Chiefs of Staff said that the missile was fired from Pyongyang at around 10:38 p.m. local time, and that it flew for approximately 570 kilometers before landing in the Sea of Japan.
The Joint Chiefs confirmed that it was a short-range weapon, ending speculation that North Korea had fired an intercontinental ballistic missile (ICBM). According to Yonhap, South Korea's First Deputy National Security Adviser Kim Tae-hyo had warned earlier that week that North Korea might launch an ICBM this month.
South Korea called the launch a "clear" violation of U.N. Security Council resolutions prohibiting North Korea from using ballistic technologies.
"While elevating our alert readiness, our military is maintaining a full readiness posture by closely sharing data on the 'North Korean ballistic missile' with the United States and Japan," the Joint Chiefs said.
The three allies have bolstered their trilateral security partnership in the wake of escalating tensions with North Korea.
The countries have also monitored weapons transfers between North Korea and Russia. In a joint statement issued Oct. 25, the U.S., South Korea, and Japan condemned the arms agreement bewteen Moscow and Pyongyang.
Russia and North Korea have officially denied reports of an arms deal, though intelligence reports and media accounts indicate that weapons transfers have begun.
The U.S. believes Pyongyang is supplying Moscow with weapons for its war against Ukraine in exchange for advanced Russian technologies that can improve North Korea's nuclear program.
On the same day that North Korea launched the missile, the Russian Defense Ministry announced that its Strategic Missile Forces loaded an RS-24 Yars ICBM into a silo in Kaluga Oblast.