Her remarks came a day after a local official led a petition signed in blood opposing the planned deployment of THAAD (Terminal High Altitude Area Defense) in Seongju, almost 300 kilometers (186 miles) southeast of the capital.
South Korea and the United States picked the mountainous southern town of Seongju as the location to deploy a Terminal High Altitude Area Defense (THAAD) system on Wednesday, as the allies are speeding up efforts to put in place the anti-ballistic missile shield to counter North Korea's growing nuclear and missile threats.
South Korea and the US repeated their assertions that the Thaad system would be a deterrent to North Korea's nuclear and missile ambitions and said it was not directed at any other nation.
South Korea's defense ministry has said it aims to have the system operational by the end of 2017. South Korean media reported the THAAD system will be placed on a mountain where a South Korea air defence artillery unit is based.
A potential backlash from China against the deployment of a missile defense system on the Korean peninsula is raising worries among South Korea's tourism and leisure industries that increasingly rely on Chinese tourists to drive sales.
The piece warned economic sanctions may expand to the whole Gyeongsangbuk-do Province, the largest in South Korea.
Having signed a petition with his own blood, Seongju County chief Kim Hang-gon led a group of protesters to the defense ministry - where officials attempted to allay concerns about health and environmental risks posed by THAAD's powerful radar.
The town's relatively remote distance from China, which bitterly opposes the deployment, has also apparently played into the decision. On Monday, North Korea warned it will take unspecified "physical" measures once the location for THAAD is announced.
China and Russian Federation oppose the system that they believe helps US radar track missiles in their countries.
North Korea is believed to be in possession of some 1,000 ballistic missiles, and 85 percent are targeting South Korea, according to the South Korean military.
Tensions have soared since Pyongyang carried out its fourth nuclear test in January, followed by a series of missile launches that analysts say show the North is making progress toward being able to strike the US mainland.
South Korean Finance Minister Yoo Il-ho told parliament the government was making contingency plans in case China took action in response to the deployment.
Some 300 Seongju locals and other supporters visited the Defense Ministry to protest.
The county's commissioner has been on a hunger strike against the deployment, county official Kim Jee-hyun said.
Seongju is a town of 45,000 people, many of them grow yellow melons for a living.