The proposed deployment of the Terminal High Altitude Area Defense (THAAD) system in South Korea has caused controversy domestically and in neighboring countries.

China reiterated its opposition to the THAAD deployment on Monday, after South Korea's Lotte Group approved a land swap with the government that will enable the deployment of the system. It has also proved controversial in South Korea, with thousands turning out to protest.

THAAD is a United States Army anti-ballistic missile system designed to shoot down short, medium, and intermediate range ballistic missiles in their terminal phase using a hit-to-kill approach. THAAD was developed to counter Iraq's Scud missile attacks during the Gulf War in 1991. The missile carries no warhead, but relies on the kinetic energy of impact to destroy the incoming missile.

A kinetic energy hit minimizes the risk of exploding conventional warhead ballistic missiles, and nuclear tipped ballistic missiles will not detonate upon a kinetic energy hit.