The U.S. Immigration and Customs Enforcement (ICE) agency has arrested hundreds of workers at a factory being built in Georgia to make car batteries for Hyundai and Kia electric, sparking protest from the South Korean government.

The Guardian reports that the September 4 raid stopped construction at the facility, which would be the biggest industrial investment in the state’s history, and had been hailed as a huge boost for the economy by Georgia’s Republican governor, Brian Kemp.

According to the Atlanta office of the U.S. justice department agency, the Bureau of Alcohol, Tobacco, Firearms and Explosives, at least 450 people were arrested. But the Korea Economic Daily later reported that around 560 workers at the Hyundai facility and LG Energy Solution (LGES) had been detained, citing unidentified industry sources. 

According to local media reports, the majority of those detained -- around 300 -- are South Korean nationals. Hyundai Motor is a South Korean automotive company with many international plants. According to BBC News, the South Korean foreign ministry called the arrests and detainment an "unjust infringement" of their rights.

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An agent at the Department of Homeland Security (DHS) said multiple federal agencies, including Ice, the FBI and the DEA “conducted a judicially authorized enforcement operation, as we are actively conducting an investigation into unlawful employment practices.”

“Arrests are being made,” Steven Schrank, the special agent in charge of homeland security investigations for Georgia, said in a news briefing.

Hyundai Motor Company said it was aware of the incident at the HL-GA Battery Company construction site and was "working to understand the specific circumstances."

"As of today, it is our understanding that none of those detained is directly employed by Hyundai Motor Company," it said in statement. "We prioritize the safety and well-being of everyone working at the site."