It came shortly after the presidential office announced the results of its week-long probe into the alleged lack of transparency in the process of bringing in and deploying the THAAD equipment.

South Korea has provided the USFK with the land for the THAAD battery under the bilateral Status of Forces Agreement.

They are required to conduct a survey of the site to help identify a possible source of the contamination.

But Han's ministry has apparently been going easy on the process, Cheong Wa Dae said, amid widespread speculation that it has pushed for an early THAAD deployment here without due procedures.

Moon, a liberal leader, has demanded a parliamentary review of the whole process related to his predecessor's controversial decision on THAAD.

The allies initially planned to complete the installation by the end of this year but a thorough environmental survey is expected to take quite a long time.

Two THAAD interceptor launchers are already operational at the site, along with a powerful X-band radar and fire-control and communication-support equipment.

Until recently, Moon had not been informed of four additional launchers stored at the USFK base. A THAAD battery needs at least eight launchers for full operation.

Cheong Wa Dae said Wee Seung-ho, deputy defense minister for policy, was behind the ministry's deliberate concealment of the information. He was immediately unseated from the position.

It said there will be further investigation, as it remains unconfirmed whether the minister or Kim Kwan-jin, former President Park Geun-hye's national security advisor, is directly involved in that. (Yonhap)