Cheonan sinking

The ROKS Cheonan (PCC-772), a Pohang-class corvette of the Republic of Korea Navy, sank on 26 March 2010 near Baengnyeong Island in the Yellow Sea, close to the disputed Northern Limit Line (NLL). Of the 104 crew aboard, 46 sailors died. The vessel broke in two and sank rapidly, prompting one of the largest peacetime salvage and forensic operations in South Korean naval history.

Seoul convened a Joint Civilian-Military Investigation Group that included experts from the United States, United Kingdom, Australia, and Sweden. Its report, released on 20 May 2010, concluded that the Cheonan was destroyed by an external underwater explosion caused by a CHT-02D torpedo fired by a North Korean midget submarine. Investigators recovered torpedo parts bearing Korean-language markings consistent with North Korean munitions.

North Korea denied involvement. China and Russia declined to endorse the findings; a Russian naval team that reviewed the evidence reportedly remained skeptical, and Beijing blocked direct attribution at the UN Security Council. On 9 July 2010, the Council issued a Presidential Statement (S/PRST/2010/13) condemning the attack but not naming North Korea as the perpetrator.

In response, South Korea announced the 24 May Measures, suspending nearly all inter-Korean trade and exchanges (excluding the Kaesong Industrial Complex), barring DPRK vessels from ROK waters, and resuming psychological-warfare broadcasts along the DMZ. The United States and South Korea conducted joint naval exercises in the months that followed.

The incident, combined with the shelling of Yeonpyeong Island in November 2010, marked one of the sharpest deteriorations in inter-Korean relations since the 1953 Armistice. It reinforced debates over the legal status of the NLL, the credibility of UNSC enforcement on the Korean Peninsula, and the role of asymmetric naval warfare in regional deterrence postures.