SEOUL, South Korea (AP) -- South Korea on Friday expressed "concern and regret" over a major U.S. immigration raid at a sprawling Georgia site where South Korean auto company Hyundai manufactures electric vehicles, which officials said led to the detainment of an unspecified number of South Korean nationals.

South Korea's Foreign Ministry spokesperson, Lee Jaewoong, read a statement following South Korean media reports that the raid by U.S. Immigration and Customs Enforcement resulted in the detainment of around 450 people, including 30 South Korean nationals. Lee did not specify exactly how many South Koreans were detained but called the number "large."

Thursday's raid targeted one of Georgia's largest and most high-profile manufacturing sites, touted by the governor and other officials as the largest economic development project in the state's history. Hyundai Motor Group, South Korea's biggest automaker, began manufacturing EVs a year ago at the $7.6 billion plant, which employs about 1,200 people, and has partnered with LG Energy Solution to build an adjacent battery plant, slated to open next year.

ICE spokesman Lindsay Williams confirmed that federal authorities were conducting an enforcement operation at the 3,000-acre (1,214-hectare) site west of Savannah, Georgia. He said agents were focused on the construction site for the battery plant.

"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," Lee said.

Lee said the ministry is taking active measures to address the case, dispatching diplomats from its embassy in Washington and consulate in Atlanta to the site, and planning to form an on-site response team centered on the local mission.

The Department of Homeland Security said in a statement that agents executed a search warrant "as part of an ongoing criminal investigation into allegations of unlawful employment practices and other serious federal crimes."

It did not say whether anyone was detained or arrested.

President Donald Trump's administration has undertaken sweeping ICE operations as part of a mass deportation agenda. Immigration officers have raided farms, construction sites, restaurants and auto repair shops.

The Pew Research Center, citing preliminary Census Bureau data, says the U.S. labor force lost more than 1.2 million immigrants from January through July. That includes people who are in the country illegally as well as legal residents.

Hyundai and LG's battery joint venture, HL-GA Battery Company, said in a statement that it's "cooperating fully with the appropriate authorities" and paused construction to assist their work.

Operations at Hyundai's EV manufacturing plant weren't interrupted, said plant spokesperson Bianca Johnson.

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Bynum reported from Savannah, Georgia.