According to sources, as cited by the Yonhap news outlet, the missile system, which was previously stationed in the North Gyeongsang province, was transferred earlier in January to a former military installation at Mount Bukak near the presidential office.
The US-built system is believed to be equipped with PAC-2 and PAC-3 missiles that are designed to intercept aircraft and missiles, the outlet said.
The South Korean military has been pushing for the relocation of the missile system since 2017.
In late December, North Korean leader Kim Jong-un said North Korea would continue developing nuclear weapons and would introduce a new strategic weapon in the near future since it did not see that its efforts for denuclearization were being met by Washington, which continued to supply strategic weapons to Seoul.