South Korea sent a chartered plane to collect workers detained in an immigration raid at a Hyundai-LG Energy Solution battery plant in Georgia last week.

Nearly 500 workers, including 300 South Korean nationals, were rounded up in the Sept. 4 raid carried out by the Department of Homeland Security (DHS). The administration has touted the move as President Trump's most ambitious enforcement effort yet.

Officials from Seoul on Wednesday sent a Boeing 747-8I from Korean Air to pick up nationals held at a detention center in Folkston, Ga, The Associated Press reported. U.S. immigration authorities will bus the detainees 285 miles to Atlanta, where they will board the charter plane for removal.

DHS said some of the detained workers entered the country illegally, while others arrived legally but stayed on expired visas. Other detainees were permitted to be in the U.S. but were prohibited from working.

South Korean officials have reportedly been negotiating with the U.S. to secure "voluntary" departures, rather than deportations. If deported, the workers could face penalties making them ineligible to return to the U.S. for up to 10 years.

The enforcement operation has increased tensions between the U.S. and one of its closest allies. On Tuesday, South Korean President Lee Jae Myung called the raid "an unjust infringement."

“I hope that there will never again be any unjust infringement on the activities of our citizens and businesses, which are essential for the mutual development of both South Korea and the United States,” Lee said at a Cabinet meeting on Tuesday, the Asia Business Daily reported.

It also comes after South Korea agreed to a 15-percent tariff rate earlier this summer, while also boosting energy investments in the U.S. Lee met with Trump at the White House last month, where he lauded the president.

"Because of the importance of the Korea-U.S. alliance, I was confident that he would not inflict a wound to our alliance," he said at the time.

The Associated Press contributed to this report.