The U.S. military on Wednesday began moving components of the controversial THAAD anti-missile system to a South Korean deployment site, amid heightened fears over the North’s nuclear plans. The move comes one day after Pyongyang boasted its “largest ever” live-fire drill, supervised by leader Kim Jong Un and featuring more than 300 large-caliber, self-propelled artillery guns along its east coast. South Korea’s defense ministry issued a statement Wednesday saying parts of the Terminal High Altitude Area Defense system were moved to the site in response to the North’s provocations. “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’s statement said. The military trailers transporting the system to the deployment site in Seongju, about 155 miles from Seoul, were met by protesters hurling water bottles and condemning what they described as U.S. occupation.