South Koreans on Tuesday held a rally at the defense ministry in Seoul against the planned deployment of an anti-ballistic missile shield as the ministry signed a formal swap deal for the system's installation.

Some 40 protesters gathered at the ministry to protest the Terminal High Altitude Area Defense system, shouting slogans and holding banners reading "THAAD out", an epa journalist reports.

Around 400 policemen were deployed for security and the protests were peaceful, with no incidents reported.

The South Korean defense ministry on Tuesday inked a land swap deal with conglomerate Lotte Group after the company agreed to provide land for the installation of the shield, according to Yonhap news agency.

Lotte handed over a $79-million golf course in Seongju County, in the southeast province of North Gyeongsang and about 300 kilometers southeast of the capital, in exchange for a state-owned military property near Seoul.

The anti-missile system will be located in this area, which is relatively isolated from residential areas.

The project was originally planned to be installed in the nearby Seongju base, but residents of the county voiced strong protests, believing that the system's radars could cause disease and damage crops, as well as put them in the spotlight in the event of a North Korean attack.

"We will make the system operational as quickly as possible to better safeguard the well-being of our nation and the lives of citizens against North Korea's growing nuclear and missile threats," the Ministry of Defense said in a statement, adding that the system will be installed “within this year”.

The system is expected to be installed between May and July this year.

However protesters are still concerned about the new location and the dangers they believe the system poses to them.

Seoul and Washington signed an agreement on the anti-missile system in July 2016 as a counter measure against North Korea's ongoing missile threats, and hope to deploy it by the end of 2017.

Pyongyang, which in 2016 conducted its fifth nuclear test and test-fired 24 ballistic missiles, sees the deployment as a direct threat against its territory.