THAAD deployment by South Korea

On 7 February 2016, South Korea announced consultations over the deployment of the Terminal High Altitude Area Defense (THAAD) system, which was officially announced to be implemented on 8 July 2016. The deployment was strongly opposed by China and Russia. South Korea argued that this military deployment was only a defensive measure to deal with North Korea, while China believed that the deployment of the THAAD system would affect its national security and took a number of countermeasures against South Korea, including implementing a Hallyu ban. These measures also led to a rapid deterioration of relations between China and South Korea.

On 6 March 2017, the system's launchers arrived in South Korea, and the South Korean side said that the system would be in service as early as April. On 26 April, two launchers were deployed in Seongju County, North Gyeongsang Province, and on 12 September, the temporary deployment of the remaining four launchers was completed. All six launchers were confirmed to have normal fire control radar and were in operational status. On 22 November, China and South Korea reached a consensus, and the South Korean side stated that it "will not consider adding THAAD system, will not join the US anti-missile system, will not develop the trilateral military alliance of South Korea, the United States and Japan, and has no intention of harming China's security interests". Since then, relations between the two countries have gradually warmed up.