Officially, the US claims it is deploying the THAAD to protect South Korea from potential missile threats from Pyongyang.
The controversial move has been met with criticism, with Russia announcing that the deployment violates a strategic balance in the region and could serve as one of the factors toward Russia's withdrawal from the New START (Strategic Arms Reduction Treaty).
Seoul and Washington agreed to deploy the THAAD system, designed to intercept short, medium and intermediate ballistic missiles at the terminal incoming stage, in July 2016, amid South Korea's growing unease about Pyongyang's nuclear program.
