The car workers arrested in one of the largest ever U.S. workplace immigration raids had violated their visitor visas, officials say.

Immigration and Customs Enforcement (ICE) stated that 475 individuals—mostly South Korean citizens—were discovered working illegally at a Hyundai facility in Georgia on Thursday. People on short-term or recreational visas are not authorized to work in the U.S., ICE asserted, emphasizing that the operation was crucial for safeguarding American jobs.

In response, South Korea has sent diplomats to Georgia to advocate for the rights of their citizens, highlighting potential diplomatic strains as South Korean companies prepare to invest in U.S. industries to avoid tariffs.

The arrested workers are currently being held at an ICE facility in Folkston, Georgia. Notably, of those detained, 300 are reported to be Korean nationals, though Hyundai clarified that none of them were direct employees. ICE claimed this operation is part of an ongoing criminal investigation and that those arrested were found to be working illegally.

However, some individuals, including clients of immigration lawyer Charles Kuck, were reported to have been wrongfully detained under a visa waiver program allowing them to travel for up to 90 days for business or tourism.

A focus of Trump's administration is on controlling illegal immigration whilst promoting foreign investment. President Trump defended the raid by calling the detained individuals 'illegal aliens' and stating that ICE was simply performing its duties. However, the implications of this crackdown on illegal work could complicate the U.S.-South Korea relationship, particularly as the factory in question is a significant economic project in Georgia.

As the landscape of U.S. immigration law continues to evolve, this raid serves as a stark illustration of the tensions between immigration policies and the need for a skilled workforce within expanding industries.