South Korea on Friday expressed “concern and regret” following a major U.S. immigration raid at a sprawling Georgia site where South Korean auto giant Hyundai is manufacturing electric vehicles. The operation by U.S. Immigration and Customs Enforcement (ICE) led to the detainment of an unspecified but “large” number of South Korean nationals, according to Seoul.

Lee Jaewoong, spokesperson for South Korea’s Foreign Ministry, read a statement addressing the incident, which came after South Korean media reported that Thursday’s raid resulted in the detention of approximately 450 people, including around 30 South Korean citizens. While Lee did not confirm the exact number of South Koreans detained, he emphasized the significant scale of those affected.

The raid targeted the construction site for a battery plant, a joint venture between Hyundai Motor Group and LG Energy Solution, adjacent to Hyundai’s $7.6 billion EV assembly plant west of Savannah. Governor Brian Kemp and other officials have lauded the 3,000-acre (1,214-hectare) complex as the largest economic development project in Georgia’s history. The Hyundai EV plant, which began manufacturing a year ago and employs about 1,200 people, is a key component of South Korea’s significant investment in the U.S. clean energy sector. The battery plant is slated to open next year.

ICE spokesman Lindsay Williams confirmed federal authorities were conducting an enforcement operation at the site, with agents focusing on the battery plant’s construction area. The Department of Homeland Security (DHS) provided further context in a statement, indicating that agents executed a search warrant “as part of an ongoing criminal investigation into allegations of unlawful employment practices and other serious federal crimes.”

Seoul underscored the importance of its investments and the rights of its citizens. “The business activities of our investors and the rights of our nationals must not be unjustly infringed in the process of U.S. law enforcement,” spokesperson Lee Jaewoong stated emphatically.

In response to the detentions, the South Korean Foreign Ministry announced it is taking active measures, dispatching diplomats from its embassy in Washington D.C. and consulate in Atlanta to the site. The ministry also plans to form an on-site response team centered on the local mission to assist its nationals.

The incident highlights growing South Korean investment in the U.S., particularly in the Southeast. Other South Korean companies with operations or planned investments in the region include SK On and Qcells, focusing on EV batteries and solar energy respectively, and agricultural equipment manufacturer TYM (formerly Branson Tractors), headquartered in Rome, Georgia.