South Korea's government has held an emergency meeting and vowed to swiftly respond to the arrests of hundreds of its citizens in a massive immigration raid at a Hyundai plant in the US.

Seoul has dispatched diplomats to the site in Georgia, while LG Energy Solution, which operates the plant with Hyundai, said it was suspending most business trips to the US.

US officials detained 475 people - mostly South Korean nationals - who they said were found to be illegally working at the battery facility, one of the largest foreign investment projects in the state.

The White House defended the operation, dismissing concerns that the raid could deter foreign investment.

They were illegal aliens and ICE [Immigration and Customs Enforcement] was just doing its job, President Donald Trump said following the raids on Friday.

Video released by ICE officials showed Asian workers shackled in front of a building, with some wearing yellow vests with names such as Hyundai and LG CNS....

On Saturday, LG Energy Solution said it was sending its Chief Human Resources Officer Kim Ki-soo to the Georgia site on Sunday. We are making all-out efforts to secure the swift release of detained individuals from our company and partner firms, it said in a statement to the South Korean media.