"The Chinese side has repeatedly expressed its concern and disagreement on this issue [deployment of THAAD in Korea]. China will undertake all the necessary steps to protect its security interests. At the same time, we call on the corresponding sides to take into consideration China's legitimate concern and to end the ongoing process," Hua said.
The deployment of the THAAD systems would significantly undermine the power balance in the region, she added.
Hua added that she hoped Washington and Seoul would refrain from the activities that could result in escalation of tensions.
China has repeatedly opposed the THAAD deployment in Korea, arguing the system could be applied beyond deterring North Korea and affect Chinese interests in the region.