Only a dozen trailers will enter the base to take such heavy equipment as forklifts and bulldozers out of it. Those were used for early-stage construction work a few months ago.

More than 400 soldiers of the allies are stationed at the former golf course to operate the system, formally called Terminal High Altitude Area Defense.

The ministry cited the need to improve their living conditions at the new base.

"Currently, the living conditions of the troops are poor," the ministry's spokesperson Choi Hyun-soo told reporters earlier in the day.

For instance, she added, it's urgent to repair leaky roofs and build sewage treatment facilities.

Choi said only the materials and equipment necessary for related works will be bought in.

But some local residents and progressive activists suspected that the military may be seeking to expand helipads and other facilities associated with military operations.

They do not want the THAAD base in Seongju, 300 kilometers south of Seoul, which was once a quiet town known for melon farming.

The military turned down a request by the protesters' group to allow a representative to monitor the on-site delivery of the materials and equipment.

"As the US military has not permitted it out of concern for security, I know that no deal has been reached on the matter," Choi said.

Last year, the US installed six THAAD launchers at the site, along with a powerful X-band radar station and a fire control and communications unit, in a bid to counter North Korea's missile and nuclear threats. The THAAD battery was immediately put in operation. (Yonhap)