Construction materials and daily necessaries were brought onto the US THAAD missile defense base in South Korea on Tuesday to improve living conditions for service members, the defense ministry said.

Earlier in the day, the military moved construction equipment and materials, as well as daily necessaries for service members, such as water onto the US Forces Korea (USFK) base in the central town of Seongju, which hosts the Terminal High Altitude Area Defense (THAAD) system.

Residents opposed to the THAAD base clashed with police as they tried to block the shipment.

"Work to improve facilities at the base is under way, which is meant to protect the basic human rights of the Korean and American service members who have been suffering from poor living conditions. It was the minimum required step," ministry spokesperson Boo Seung-chan said.

The ground transport was inevitable as those items are too heavy to be airlifted, Boo said, stressing that no weapons or other items to upgrade or strengthen the unit are included.

Since the establishment of the base in 2017, hundreds of US and South Korean service members have used shipping containers and an old golf clubhouse there, and Seoul and Washington pledged joint efforts to better the living conditions.

As an integral part of the US-led missile defense system, THAAD is designed to shoot down short-, medium- and intermediate-range ballistic missiles at a high altitude in their terminal phase, using a hit-to-kill method.

South Korea and the US said the system aims to better cope with the growing missile threats posed by North Korea. (Yonhap)