Amid mounting tension over North Korea’s missile and nuclear programs, the U.S military started moving parts of its controversial THAAD anti-missile defense system to a deployment site in South Korea on Wednesday, according to a Reuters report.

The earlier-than-expected move prompted protests by hundreds of local residents while a spokesman for Moon Jae-in, a presidential candidate, said the decision "ignored public opinion and due process" and demanded the deployment be suspended until the next administration was in place and had made its policy decision, Reuters reported.

The U.S and South Korea last year agreed to deploy the Terminal High Altitude Area Defense (THAAD) system to counter the threat of missile launches by North Korea. However the move has angered China, which says the advanced system will do little to deter the North while destabilizing the regional security balance.

Reuters stated that according to the South Korean defense ministry, some elements of THAAD were moved to the site on what had been a golf course in the south of the country.

"South Korea and the United States have been working to secure an early operational capability of the THAAD system in response to North Korea's advancing nuclear and missile threat," the ministry said in a statement. The battery is expected to be operational by the end of the year, it added.

Reuters stated that the Pentagon said the deployment was a critical measure to defend South Korea and its allies against North Korean missile threats and it would complete it "as soon as feasible".