Hundreds of federal agents descended on a sprawling site where Hyundai manufactures electric vehicles in Georgia and detained 475 people, most of them South Korean nationals.

This is the latest in a long line of workplace raids conducted as part of the Trump administration's mass deportation agenda. But the one on Thursday is especially distinct because of its large size and the fact that it targeted a manufacturing site state officials have long called Georgia's largest economic development project.

The detainment of South Korean nationals also sets it apart, as they are rarely caught up in immigration enforcement compared to other nationalities.

Video released by U.S. Immigration and Customs Enforcement on Saturday showed a caravan of vehicles driving up to the site and then federal agents directing workers to line up outside. Some detainees were ordered to put their hands up against a bus as they were frisked and then shackled around their hands, ankles and waist. Others had plastic ties around their wrists as they boarded a Georgia inmate-transfer bus.

South Korea’s Foreign Minister Cho Hyun said Saturday that more than 300 South Koreans were among the 475 people detained.

Some of them worked for the battery plant operated by HL-GA Battery Co., a joint venture by Hyundai and LG Energy Solution that is slated to open next year, while others were employed by contractors and subcontractors at the construction site, according to Steven Schrank, the lead Georgia agent of Homeland Security Investigations.

He said that some of the detained workers had illegally crossed the U.S. border, while others had entered the country legally but had expired visas or had entered on a visa waiver that prohibited them from working.

But an immigration attorney representing two of the detained workers said his clients arrived from South Korea under a visa waiver program that enables them to travel for tourism or business for stays of 90 days or less without obtaining a visa.

The detainees also included a lawful permanent resident who was kept in custody for having a prior record involving firearm and drug offenses, since committing a crime of “moral turpitude” can put their status in jeopardy, Lindsay Williams, a public affairs officer for U.S. Immigration and Customs Enforcement, said Saturday.

Williams denied reports that U.S. citizens had been detained at the site since “once citizens have identified themselves, we have no authority.”

Hyundai Motor Company said in a statement Friday that none of its employees had been detained as far as it knew and that it is reviewing its practices to make sure suppliers and subcontractors follow U.S. employment laws. LG told The Associated Press that it couldn’t immediately confirm how many of its employees or Hyundai workers had been detained.

Most of the people detained have been taken to an immigration detention center in Folkston, Georgia, near the Florida state line. None of them have been charged with any crimes yet, Schrank said, but the investigation is ongoing.