South Korea has sent a chartered Korean Air flight to the United States as part of urgent efforts to bring home hundreds of its citizens detained in what has been described as the largest immigration raid in recent US history.

The raid, carried out at a USD 4.3 billion Hyundai-LG battery plant construction site in Georgia, saw 475 people arrested last week, the majority of them South Koreans. Immigration agents said the operation was the biggest single-site crackdown conducted under former president Donald Trump’s immigration policies.

A Korean Air Boeing 747-8I, with capacity for more than 350 passengers, departed Seoul on Wednesday morning bound for the US, according to the airline. A spokesperson confirmed the departure but said the timeline for the return flight had not yet been finalized. Local broadcasts showed footage of the aircraft taking off from Incheon International Airport.

South Korea’s foreign minister Cho Hyun has been in Washington since Monday to negotiate with US officials, calling the arrests a “grave situation.” Before leaving Seoul, Cho told lawmakers that “a tentative agreement” had been reached to ensure the detained workers would not face long-term penalties, including a five-year re-entry ban. “I can tell you that negotiations are going well,” he assured MPs.

Cho also met with US Secretary of State Marco Rubio, who emphasized Washington’s interest in maintaining close ties with Seoul. Rubio said the United States “welcomes ROK investment into the United States and stated his interest in deepening cooperation on this front,” according to a State Department statement.

South Korean officials in Georgia, including consular representatives in Atlanta, have been coordinating with local authorities to monitor conditions and expedite the workers’ release. Cho acknowledged the gravity of the situation, telling business leaders in Washington, “I feel a great responsibility that our citizens have been arrested in this manner.”

Experts believe many of the detained South Koreans entered the United States on visas that did not authorize construction labor, creating a legal gray area that left them vulnerable. US-licensed attorney Yum Seung-yul suggested the incident could drive Seoul to push for a special visa arrangement tailored for South Koreans working in American projects.

The mass detention comes at a delicate moment in South Korea-US relations. As Asia’s fourth-largest economy, South Korea has invested heavily in American industries in response to Washington’s repeated calls for global partners to expand production on US soil. The battery plant in Georgia, a joint venture between Hyundai and LG Energy Solution, is among the most significant of these projects.

Despite assurances from both governments that the alliance remains strong, the incident has sparked unease in Seoul, where the priority is now securing the swift and safe return of the detained workers.