South Korea's foreign minister will travel to the United States on Monday to help secure the return of hundreds of Koreans who were detained in Georgia last week.
US officials detained 475 people - more than 300 of them South Korean nationals - who they said were illegally working at a car battery plant.
The facility is being built by two South Korean companies – Hyundai and LG - and is one of the largest foreign investment projects in the state.
Such raids have ramped up under President Donald Trump who has vowed to crack down hard on unauthorised immigration. But Friday's raid could become a source of tension with a key ally, South Korea, which has also promised to invest in the US.
South Korea expressed "concern and regret" over the operation and urged the US government to respect the rights of its citizens.
