Donald Trump has called on foreign companies investing in the United States to respect immigration laws and prioritise training American workers, after federal agents detained nearly 500 people in what authorities described as the largest single-site immigration enforcement action in U.S. history.

The raid at Hyundai’s battery plant in Ellabell, Georgia, where U.S. officers arrested about 475 workers, including roughly 300 South Korean nationals. The operation, carried out with armoured vehicles and heavily armed agents, followed a months-long investigation into suspected hiring violations by subcontractors at the site.

Footage showing workers shackled and escorted by agents drew criticism in Seoul. The South Korean government expressed regret and arranged to repatriate its nationals, while Hyundai emphasised that those detained were not directly employed by the company.

Responding to the incident, Trump wrote on Truth Social that while foreign investors were welcome, they must comply with U.S. immigration rules. “What we ask in return is that you hire and train American workers,” he said, while adding that companies would be able to legally bring in skilled foreign staff to support technology transfer and training.

Trump told reporters the raid had not affected his ties with South Korea but said he would review the details of the enforcement action. He also indicated he was open to allowing foreign manufacturing experts into the country temporarily to help build U.S. capacity.

The Ellabell facility, a joint project of Hyundai and LG Energy Solution worth over 7 billion U.S. dollars, is one of the largest industrial investments in Georgia’s history.