By Austin Alonzo

Work at Hyundai’s Georgia complex that manufactures electric vehicles has been suspended after federal authorities detained hundreds of workers in a major immigration enforcement operation on Thursday, officials said.

On Sept. 4, federal authorities entered a worksite in Bryan County, Georgia, where South Korean manufacturing companies Hyundai Motor Group and LG Energy Solution are building a $4.3 billion battery cell manufacturing plant.

Authorities from the Department of Homeland Security and the Justice Department said that about 450 workers were detained. A number of South Korean nationals were detained.

A spokesperson at Hyundai’s battery joint venture partner, South Korean battery maker LG Energy Solutions, said construction had been paused and that it was cooperating with law enforcement.

In a Sept. 5  statement, South Korea’s Foreign Ministry said that “many” South Korean nationals were detained during the operation.

“The economic activities of our companies investing in the United States and the interests of our citizens must not be unduly violated during the course of U.S. law enforcement,” ministry spokesperson Lee Jae-woong said.

In a press briefing conducted near the site on Sept. 4, Steven Schrank, the special agent in charge of Homeland Security investigations for Georgia, said the operation was “judicially authorized” as the agency is looking into unlawful employment practices at the construction site.

In a follow-up briefing on Sept. 5, Schrank said that 475 people were arrested, of whom a majority were South Korean nationals. So far, he said, no charges have been filed.

Schrank called the operation “the largest single-site enforcement operation in the history of Homeland Security investigations.”

The plant is being built by HL-GA Battery Company, a joint venture between Hyundai and LG Energy Solution, at Hyundai’s existing electric vehicle assembly metaplant near Savannah, Georgia. The battery plant is expected to produce batteries for Hyundai, Kia, and Genesis electric vehicles. It is part of Hyundai’s broader $12.6 billion investment in Georgia.

In March, leaders of Hyundai and Kia joined local dignitaries, including Georgia Gov. Brian Kemp, to celebrate the opening of the Hyundai Motor Group Metaplant America in Ellabell, Georgia. They called the cumulative effort the largest economic development project in Georgia’s history.

The immigration enforcement operation is part of a broader push by the Trump administration to crack down on the employment of illegal immigrants. In a statement on Sept. 4, DHS and U.S. Citizenship and Immigration Services (USCIS) hailed the expanded authority of USCIS special agents, who are now empowered to “investigate, arrest, and present for prosecution those who violate America’s immigration laws,” they said.

Reuters contributed to this report.