Atlanta, Georgia. A plane carrying more than 300 workers from South Korea who were detained during an immigration raid at a battery factory in Georgia last week left Atlanta shortly before noon Thursday, bound for South Korea.

The workers traveled by bus from a detention center in southeast Georgia to Atlanta earlier in the day for their flight, which is expected to land in South Korea on Friday afternoon. South Korea’s Foreign Ministry said the detainees released by US authorities included 316 Koreans, 10 Chinese nationals, three Japanese nationals, and one Indonesian.

More than 300 Koreans were among about 475 workers detained during last week’s raid at the battery factory under construction on the campus of Hyundai’s sprawling auto plant west of Savannah.

The workers had been held at an immigration detention center in Folkston, 285 miles (460 kilometers) southeast of Atlanta.

South Korea's President Lee Jae Myung called Thursday for improvements to the United States' visa system, saying Korean companies will likely hesitate to make new investments in the US until that happens.

Lee said during a news conference that Korean and US officials had a back-and-forth discussion over whether the detainees had to be handcuffed while they traveled by bus to Atlanta -- something the Koreans “strongly opposed." He said there was also a debate over whether they would be leaving under “voluntary departure” or deportation.

While those discussions were ongoing, US officials started to return the detainees' belongings. Then, however, “everything suddenly halted," Lee said, adding that they were told that was due to instructions from the White House.

“President Trump had directed that the (detainees) should be allowed to return home freely and those who didn’t want to go didn’t have to,” he said. "We were told that, because of that instruction, the process was paused and the administrative procedures were changed accordingly.”

A South Korean Foreign Ministry official, speaking on condition of anonymity to discuss the diplomatic process, said Trump had halted the process to hear from South Korea on whether the Koreans should be allowed to stay to continue their work and help train US workers or should be sent back to South Korea.

Lee said during his news conference that the US gave the detainees a choice between staying and going home. Ultimately, one South Korean national who has relatives in the US chose to stay, Lee said.