SEOUL/WASHINGTON – The detention of more than 300 South Korean engineers in the United States has sparked protests in Seoul and raised fresh questions about the strength of the U.S.–South Korea alliance, just weeks after both governments pledged deeper economic and security ties.

U.S. Immigration and Customs Enforcement (ICE) agents last week raided a Hyundai–LG battery plant construction site in Georgia, arresting 316 South Korean technicians along with dozens of other foreign workers. Authorities said the group was using short-term B-1 visas that did not permit them to work in the United States.

The engineers were released on Thursday following negotiations between Seoul and Washington and flew home Friday on a chartered Korean Air flight. One Korean national chose to remain in custody to pursue a legal challenge.

Outcry in South Korea

The images of workers in handcuffs and chains spread quickly on social media, fueling rare bipartisan criticism of Washington. At Incheon Airport, a protest banner read: “We are friends – or not?” depicting U.S. President Donald Trump in ICE uniform.

President Lee Jae-myung called the incident “confusing” and warned it could undermine billions of dollars in planned South Korean investments in the U.S. “This could have significant effects on future direct investment,” he said at a press conference marking his first 100 days in office.

South Korea’s conservative Chosun Ilbo newspaper wrote the arrests raised “fundamental questions” about the alliance, while liberal daily Hankyoreh described them as a “betrayal.”

Diplomatic Response

Foreign Minister Cho Hyun flew to Washington this week to meet U.S. Secretary of State Marco Rubio, pressing for a clearer visa system for Korean workers. Seoul had feared deportations, which could complicate reentry for the engineers, but the sides agreed on voluntary departure.

The episode comes only weeks after President Lee’s White House visit, which had ended with pledges of close cooperation.

Business Impact

Hyundai Motor said the raid was a setback to its U.S. strategy. José Muñoz, head of the company’s North American operations, told reporters the Georgia battery plant would face delays of “at least two to three months.”

The controversy follows other disputes between Washington and Korean industry. In August, the U.S. Commerce Department revoked waivers allowing Samsung Electronics and SK Hynix to operate in China, complicating their supply chains.

Strained Partnership

The arrests threaten to cast a shadow over a trade deal reached in July, which included $350 billion in promised Korean investments in the United States. While Seoul had agreed to expand its shipbuilding capacity to support U.S. strategy in the Pacific, President Trump has yet to finalize U.S. tariff concessions on Korean automobiles.

“The episode has unsettled our companies,” Lee said. “We will not make decisions contrary to our national interest.” (zai)