South Korean President Lee Jae Myung ordered all-out efforts on Saturday to swiftly respond to the arrests of hundreds of the nation’s citizens in a US immigration raid on a Hyundai Motor car battery factory.

Foreign Minister Cho Hyun said the government has set up a team to respond to Thursday’s arrest of over 300 Koreans at the facility in the southern state of Georgia and that he may go to Washington to meet with officials if needed.

US officials detained 475 people, mostly South Korean nationals, who they said were found to be illegally working at the battery facility, one of the largest foreign investment projects in the state.

“I am deeply concerned. I feel heavy responsibility for the arrests of our citizens,” Cho told an emergency government meeting.

The incident could exacerbate tensions between the Trump administration and Seoul, a key Asian ally and investor. They have been at odds over the details of a trade deal that includes $350 billion of South Korean investment in the United States.

Workers shackled

A video released by US Immigration and Customs Enforcement showed Asian workers shackled at the wrists, waist, and ankles getting on a bus after the raid, which involved a helicopter and armoured vehicles.

The arrest of some 475 workers, including over 300 Koreans, at the plant near Savannah, part of President Donald Trump’s escalating crackdown on immigrants, was the largest single-site enforcement operation in the US Department of Homeland Security’s history.

In the video, hundreds of workers were standing up in front of a building, with some wearing yellow vests with names such as “Hyundai” and “LG CNS.” Two of the workers hid in a pond before being arrested.

“We welcome all companies who want to invest in the US, and if they need to bring workers in for building or other projects, that’s fine — but they need to do it the legal way,” Special Agent in Charge of Homeland Security Investigations in Georgia and Alabama Steven N. Schrank, said in a statement on Saturday.

“This operation sends a clear message that those who exploit the system and undermine our workforce will be held accountable.”

Hyundai said it would investigate its suppliers and their subcontractors to ensure they meet regulations.

LG Energy Solution, which is working with Hyundai to build the factory, said it had asked employees to return from US business trips while suspending travel to the United States except for customer meetings.

LG Energy Solution said 47 of its employees and about 250 workers for contractors at the joint venture factory were detained.