The move to deploy the THAAD system, which drew a swift and sharp protest from China, came a day after the U.S. Treasury Department blacklisted leader North Korean leader Kim Jong Un for human rights abuses.
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 USA mainland.
He also said the location of the THAAD battery will protect important national facilities such as nuclear power plants and strengthen the military capabilities of the South Korea-U.S. alliance.
KCNA said the North also notified the US government on Sunday that it will close its NY diplomatic channel as part of "practical" measures taken in response to the sanctions.
South Korea's defense ministry said it will announce later on Wednesday the location of a USA military THAAD anti-missile defense unit, a planned deployment that has angered China and prompted North Korea to threaten retaliation.
North Korea's Supreme Leader Kim Jong-Un is expecting to consolidate further his control over a country that has grown increasingly unique over their pursuit of nuclear weapons.
First of all, Park - as the commander-in-chief - needs to make sure the South Korean military prevents or deals properly with any provocations from North Korea, which is reacting fiercely to the planned deployment of the Terminal High Altitude Area Defense.
China and Russian Federation have also voiced strong concerns over the THAAD battery.
Kirby urged North Korea to adhere to the Vienna Convention on Consular Relations and grant consular access to any detained USA citizens without delay.
The medium-altitude Patriot interceptor system is more effective at countering North Korea's missiles that fly shorter distances, thus at a lower altitude, he said.
An official with South Korea's Defense Ministry told CNN the USA and South Korea "will be deploying THAAD for combat as soon as possible, by the end of next year at the latest".
The two countries aim to deploy the U.S. missile defence system in the site by the end of 2017.
Now detained in North Korea is Otto Warmbier, a University of Virginia student sentenced to 16 years of hard labor for reportedly trying to steal an item that included a propaganda claim.
South Korean media also reported the choice was made to place the system as far as possible from China, which objects to the THAAD deployment because it fears the USA could use the system's radar to track its own military moves.
"We hope the people and residents in Seongju render support" for the decision, the ministry said in a statement.
South Korea and the USA announced last Friday that they had made a decision to deploy a THAAD system in South Korea to defend against the North.
Technically, the United States and North Korea are still at war because the Korean War, 1950 to 1953, only ended in a truce.
The South Korean Defence Ministry said the THAAD system would be deployed in the southeastern county of Seongju to maximize its effectiveness while minimizing any impact on residents and the environment.