South Korea mounts swift response to deal with raid on US Hyundai plant

South Korea is mounting an "all-out" response, as the country reels over the arrest of more than 300 of its citizens in an 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."

"People on short-term or recreational visas are not authorized to work in the US," ICE said, adding that the raid was necessary to protect American jobs.

"This operation sends a clear message that those who exploit the system and undermine our workforce will be held accountable," Homeland Security Investigations (HSI) Special Agent Steven Schrank said in a statement on Saturday.

South Korea, a close US ally, has pledged tens of billions of dollars in American manufacturing investment, partly to offset tariffs.

The timing of the raid, as the two governments engage in sensitive trade talks, has raised concern in Seoul.

Trump has actively encouraged major investments from other countries while also tightening visa allocations for foreign companies.

Many of the LG employees arrested were on business trips with various visas or under a visa waiver programme, officials say.

South Korea's Minister of Foreign Affairs Cho Hyun said he felt a "great sense of responsibility for the arrest of our citizens" as he presided over an emergency meeting about the issue on Saturday.

He said the government had set up a team to respond to the arrests and that he may travel to Washington if needed.

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.

"We are confirming regular medications for families through an emergency contact network for detainees and plan to request that necessary medications be delivered to those detained."

The company said it was suspending most business trips to the US and directing employees on assignment in the US to return home immediately.

South Korean media widely described the raid as a "shock," with the Dong-A Ilbo newspaper warning it could have "a chilling effect on the activities of our businesses in the United States".

The factory, which makes new electric vehicles, had been touted by Georgia's Republican governor as the biggest economic development project in the state's history, employing 1,200 people.

The arrested workers were being held at an ICE facility in Folkston, Georgia, until the agency decides where to move them next.

LG Energy Solution said 47 of its employees and about 250 workers for contractors at the joint venture factory were detained.