SEOUL, South Korea: South Korea's president warned that Korean companies may think twice before expanding in the United States unless Washington overhauls its visa system, sharpening tensions after last week's dramatic immigration raid in Georgia.

At a news conference marking his first 100 days in office, President Lee said the September 4 raid, which saw U.S. agents arrest more than 300 South Korean workers at Hyundai's battery plant site, had left a lasting impression on the public and raised questions about the risks of investing in America. Seoul has arranged for the workers' return on a charter flight on September 12.

"The United States doesn't have the workforce to build or install equipment at these facilities, yet they won't issue visas to allow our people to stay and do the work," Lee said. "If that's not possible, establishing a local facility in the United States will either come with severe disadvantages or become very difficult for our companies."

U.S. officials said some of the workers had entered the country illegally, while others overstayed visas or entered on visa waivers that prohibited employment. However, South Korean officials argue that Washington has long resisted Seoul's calls to create a visa pathway for skilled workers, even while pressing Korean firms to boost industrial investment.

The raid, carried out with armored vehicles and widely broadcast footage of workers being shackled, drew outrage across South Korea's political spectrum. Lawmakers in both ruling and opposition parties condemned the detentions, and the country's biggest newspaper likened the operation to a "rabbit hunt."

Lee described the incident as a reflection of "cultural difference," pointing out that South Korea tolerates Americans teaching English on tourist visas. "But the United States clearly doesn't see things that way," he added.

In Washington, Foreign Minister Cho Hyun said after talks with Secretary of State Marco Rubio that the U.S. had agreed to allow the detained workers to return and finish their assignments. The two governments will also form a joint working group to discuss a new visa category that would make it easier for Korean companies to send staff for short-term projects.

South Korea has more than 20 major industrial projects underway in the U.S., including additional battery plants in Georgia, a semiconductor facility in Texas, and a shipbuilding project in Philadelphia. Analysts warn that those projects could face delays unless the visa issue is resolved.

"Korean companies will no longer be able to send their workers to the United States, causing inevitable delays in the expansion of facilities and other production activities, and the harm will boomerang back to the U.S. economy," said Min Jeonghun, a professor at South Korea's National Diplomatic Academy.