Seoul said Sunday that negotiations with the United States to secure the release of South Korean workers detained in an immigration raid have "concluded" and they would soon be freed and flown home.

The announcement follows the arrest of more than 300 South Korean workers at a Hyundai-LG battery plant being built in the southern state of Georgia on Thursday.

The operation, carried out in the town of Ellabell, was the largest single-site raid implemented so far under U.S. President Donald Trump's nationwide anti-migrant drive and caught Seoul officials off-guard.