More than 300 South Korean workers arrived at Incheon International Airport on Friday after being caught in the largest-ever US immigration raid at a Hyundai-LG battery plant construction site in Georgia.

The week-long ordeal, led by Immigration and Customs Enforcement (ICE), has triggered outrage in South Korea and raised questions about the reliability of its closest ally, the United States.

The 316 Koreans, along with 14 workers of other nationalities, landed on a chartered Korean Air flight. Many appeared exhausted, carrying only small bags and wearing face masks, relieved to be back home after being detained since September 4.

South Korean media outlets condemned the US operation, with reports describing workers as being treated like “prisoners of war.”

Anger spread across the political spectrum, with editorials accusing Washington of betraying Seoul’s trust. One conservative paper called it a “merciless arrest operation,” while another described South Koreans as feeling “stabbed in the back.”

Footage released by ICE showing workers led away in chains deepened public anger, evoking memories of historical subjugation.

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Visa issues behind the crackdown

The raid stemmed from workers entering the US on B1 business visas or through the visa waiver program, which US authorities argued did not permit full employment.

Korean companies have long relied on this “grey zone” because H-1B work visas are slow to obtain, and South Korea does not enjoy the same dedicated visa quotas as other US trade partners.

Past US administrations largely overlooked this practice, but the crackdown exposed the vulnerability of Korean firms investing heavily in the United States’ electric vehicle industry.

Political fallout between South Korea and the United States

President Lee Jae Myung issued one of his strongest warnings yet to Washington, saying Korean businesses may “hesitate to make direct investments” if visa issues remain unresolved.

“The US doesn’t have such personnel, and they won’t give visas for our workers to stay and work,” Lee said, stressing the risks posed to crucial projects like the $4.3 billion Hyundai-LG plant.

South Korea’s Foreign Minister, Cho Hyun, met with US Secretary of State Marco Rubio to secure assurances that detained workers would not be restrained during transport, addressing a particularly sensitive grievance.

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Media and public anger in Seoul

The raid has sparked unprecedented criticism in South Korea. A survey by South Korean broadcaster MBC found 68% of respondents believed the United States failed to treat South Korea as an ally in handling the situation.

At Incheon Airport, protesters denounced the detention as a “national humiliation.” One 75-year-old demonstrator declared, “Trump, who do you think you are? This is evil behaviour.”

The detention of hundreds of Korean workers in the United States has escalated into a full-blown diplomatic dispute, exposing cracks in the alliance. For South Korea, the episode has become both a test of trust and a warning over its economic dependence on US markets.