The presidential office asserted on Thursday that the U.S. THAAD anti-missile system deployed in the country is a tool for self-defense.

A top office official issued the position during a briefing when asked about China's claim that Seoul agreed to the principle of the so-called "Three Noes" and restrictions on the use of the existing THAAD battery.

While noting that the foreign ministry had already spoken on its own behalf, the official reiterated that THAAD is a self-defensive system deployed for the express purpose of protecting people's lives and safety against North Korea's nuclear and missile threats, and emphasized that the issue is a matter of national security and sovereignty.

The foreign ministry said on Wednesday that the previous administration had also stated that the “Three Noes” policy was not a pledge or an agreement with China, and the continual raising of the issue regarding THAAD deployment by Beijing will hinder bilateral relations. 

Statements by China’s foreign ministry appeared to purport that Seoul officially pledged adherence to the “Three Nos” policy of no additional THAAD deployment, no participation in a U.S.-led missile defense network and no trilateral military alliance with the U.S. and Japan.