• Over 300 South Korean workers detained in a US immigration raid return home after intense diplomatic negotiations.
• Images of workers in handcuffs caused public outrage in South Korea, impacting relations with the US.
• Seoul seeks to establish new visa categories to improve labor mobility for skilled workers.
• The raid has delayed the startup of a key Hyundai battery plant, threatening future investments.
• South Korean President Lee Jae-myung warns that incidents like this could deter investment in the US.

Hundreds of South Korean workers, primarily engineers involved in a Hyundai-LG battery plant project, returned home on Friday following a significant US immigration raid that led to their detainment. The group, totaling 330, included 316 South Koreans, alongside other foreign nationals. Their chartered flight left Atlanta's Hartsfield-Jackson airport and was received with emotional reunions at Incheon International Airport, highlighting the incident's impact on families and community ties, according to Source 1 and Source 16.

The US operation, which detained a total of 475 workers, has been described as a "bewildering" assault on workers who were reportedly following established visa processes. Images of them in handcuffs sparked outrage in South Korea, leading to public protests and calls for accountability, according to Source 10 and Source 14.

South Korean President Lee Jae-myung has warned that this incident could have a lasting negative effect on future investment decisions by Korean businesses in the United States, particularly as negotiations for a substantial $350 billion investment deal remain ongoing. In response to the raid, officials from both countries are exploring the establishment of a new visa category aimed at facilitating the entry of skilled workers from South Korea, as outlined by Source 9 and Source 11.

The ramifications of the raid are pronounced in the context of US-South Korean relations, with widespread fears that such immigration crackdowns might discourage future foreign investment in manufacturing operations within the US. Many South Korean firms heavily rely on the ability to employ skilled technicians for short-term projects to help them navigate building and managing new facilities, as indicated by various industry leaders including those from Hyundai and LG Energy Solution, according to Source 4 and Source 20.

Returning workers expressed relief mixed with apprehension, unsure about the future of their employment status in the US and the implications of the raid on their professional prospects. Workers also recounted distressing conditions during their detention in Georgia, leading to broader concerns about worker rights within the immigration system, according to Source 13 and Source 16.