The ROKS Cheonan sinking occurred on 26 March 2010, when Cheonan, a Pohang-class corvette of the Republic of Korea Navy, carrying 104 personnel, sank off the country's west coast near Baengnyeong Island in the Yellow Sea, killing 46 seamen. The cause of the sinking remains in dispute, although evidence points to North Korea.

A South Korean-led official investigation carried out by a team of international experts from South Korea, the United States, the United Kingdom, Canada, Australia, and Sweden presented a summary of its investigation on 20 May 2010, concluding that the warship had been sunk by a North Korean torpedo fired by a midget submarine. The conclusions of the report resulted in significant controversy within South Korea. Following the sinking, South Korea imposed sanctions against North Korea, known as the May 24 measures.

North Korea denied that it was responsible for the sinking. North Korea's further offer to aid an open investigation was disregarded. China dismissed the official scenario presented by South Korea and the United States as not credible. The results of an investigation by the Russian Navy were not made public. The United Nations Security Council made a Presidential Statement condemning the attack but without identifying the attacker.