Foreign Minister Cho Hyun says he is ‘deeply concerned’ over detention of 300 South Koreans, while opposition calls it a ‘grave matter’.

South Korean President Lee Jae-myung has ordered all-out efforts to respond to the arrests of hundreds of the country’s citizens in an immigration raid on a Hyundai Motor-LG car battery factory in the United States.

Thursday’s arrest of some 475 workers – more than 300 of them South Korean nationals – at the plant near Savannah in the southern US state of Georgia was the largest single-site enforcement operation carried out by the Immigration and Customs Enforcement (ICE), an arm of the US Department of Homeland Security.

South Korean Foreign Minister Cho Hyun on Saturday said President Lee has instructed officials to swiftly resolve the matter, stressing that the rights and interests of South Korean nationals and the business operations of South Korean companies investing in the US “must not be infringed upon”, South Korea’s official Yonhap news agency said in a report.

Cho said the government has set up a team to respond to the arrest of more than 300 Koreans at the facility, under construction in the southern state of Georgia, and that he may go to Washington, DC, to meet with officials if needed.

“We are deeply concerned and feel a heavy sense of responsibility over the arrests of our nationals,” Cho was quoted by Yonhap before an emergency meeting on Saturday to tackle the incident.

“We will discuss sending a senior Foreign Ministry official to the site without delay, and, if necessary, I will personally travel to Washington to hold consultations with the US administration,” he said.

The plant where the raid took place – part of US President Donald Trump’s escalating immigration crackdown – is intended to supply batteries for electric vehicles.

Responding to a reporter’s question about the immigration raid, Trump on Friday remarked during an event at the White House, “I would say that they were illegal aliens, and ICE was just doing its job.”

Steven Schrank, an ICE official, justified the detentions, saying some of those detained had illegally crossed the US border, others arrived with visas that prohibited them from working, and some overstayed their work visas.

South Korea’s opposition People Power Party (PPP) reacted angrily to the detentions, warning they “could pose a serious risk” to the country.

“This is a grave matter that could lead to broader repercussions for Korean companies and communities across the United States,” PPP chairman Jang Dong-hyeok said in a statement.

Senior PPP spokesperson Park Sung-hoon blamed Lee for the incident, saying his “pragmatic diplomacy” towards the US “failed to ensure both the safety of citizens and the competitiveness” of South Korean businesses.

He said Lee’s government even promised at least $50bn of investments during his recent meeting with Trump, a gesture that only resulted in a “crackdown” against South Korean citizens.

In a statement, Hyundai said it was “closely monitoring” the situation, adding that none of those detained “is directly employed” with the company.

LG Energy Solution said it was “gathering all relevant details”, adding it “will fully cooperate with the relevant authorities”.

South Korea, Asia’s fourth-biggest economy, is a key automaker and electronics producer with multiple plants in the US. Its companies have invested billions of dollars to build factories in the US, in a bid to access the US market and avoid tariff threats from Trump.