The ruling party chief said Monday that South Korea should push for the deployment of an advanced U.S. missile defense system, citing the threats posed by North Korea's missile and nuclear programs.

Kim Moo-sung, chairman of the ruling Saenuri Party said, it's high time for South Korea to have a forward-looking and aggressive stance on the deployment of a Terminal High Altitude Area Defense battery.

"We should not passively react to North Korea's nuclear issue," Kim said in a meeting with party officials, noting South Koreans' lives are at stake because of North Korea's nuclear program.

The issue has recently gained fresh momentum in South Korea after North Korea claimed that it successfully carried out its first hydrogen bomb test last month.

Defense Minister Han Min-koo said last month that South Korea needs to consider deploying the THAAD system from the perspective of national defense.

The comments represent a clear departure from the strategic ambiguity South Korea had maintained over the issue in apparent concerns of Chinese opposition.

THAAD is designed to shoot down ballistic missiles in their terminal stage using a hit-to-kill program.

Washington says the THAAD battery is a purely defensive system designed only to counter ballistic missile threats from North Korea.

Still, China has repeatedly expressed its opposition to the possible deployment of a THAAD battery in South Korea as the radar system could monitor military facilities in China. (Yonhap)