South Korea's defense ministry said Wednesday that the US military will install the four additional THAAD launcher early Thursday morning.
President Moon Jae-in ordered the deployment of additional THAAD launchers soon after Pyongyang launched a second intercontinental ballistic missile in late July.
Even while approving the new installations-which are likely to irritate neighbors China and Russia-South Korean officials insisted the deployment was "provisional", as the environmental survey Moon demanded had not yet been completed before North Korea's alleged hydrogen bomb test this week. Japan on the other hand has supported the plans, saying it will contribute to peace and stability.
Following North Korea's repeated provocations-including launching a missile over northern Japan last week and a sixth nuclear test on Sunday-Moon appeared significantly more comfortable with the presence of the USA system over South Korea's skies.
Seoul announced the deployment of four additional US Terminal High Altitude Area Defense (THAAD) missile systems in North Gyeongsang Province following the recent nuclear test by Pyongyang, local media reported Wednesday.
The government is shifting to a tougher line on North Korea after the North's nuclear test on Sunday.
Syria regularly using chemical weapons
March 3, 2017: The OPCW says it is examining allegations of eight toxic gas attacks in Syria since the beginning of the year. The report also said the ongoing offensive to repel Daesh has displaced more than 190,000 people in Raqqa.
A THAAD battery normally consists of six launchers, but only two have been operational so far at the site in rural Seongju.
The anti-missile defence systems are meant to protect South Korea from an attack from North Korea.
The THAAD equipment was carried by about 10 USA military vehicles from Osan Air Base, some 70 kilometers south of Seoul.
Trump is to speak Wednesday with China's president.
The Ministry of Environment on Monday cleared the way for the USA military to complete the deployment, announcing that its summary study found no safety problems.
Japanese prime minister Shinzo Abe, who will meet Mr Putin in Vladivostok on Thursday, said before his departure from Japan: "We must make North Korea understand there is no bright future for the country if it pursues the current path".