Hours earlier, Adm. Harry Harris, commander of the U.S. Pacific Command (PACOM), told U.S. congressmen that the THAAD system will become operational "in the coming days."
The U.S. Forces Korea (USFK) has already installed some key components of the sophisticated weapon at the deployment site in Seongju, North Gyeongsang Province, despite fierce protests from local residents. Those include a cutting-edge X-band fire control radar and truck-mounted launchers.
Asked about comments by Harris, the ministry's spokesman Moon Sang-gyun said it means "actual operation."
"The positioning of some equipment means that South Korea and the U.S. have the capability to cope with North Korea's provocations," he said. "It means actual operation."
He added that the THAAD equipment is currently in "field deployment" at the former golf course which South Korea offered to USFK, with the allies conducting a joint environmental effect survey of the new military base under the Status of Forces Agreement (SOFA).
The official said such a field deployment of the equipment is possible without an environmental assessment.
Operating the THAAD system is also possible as well before the survey, a process expected to take weeks or months, is done, he added.