Hundreds of South Korean workers were headed back to Seoul on Friday after their detention in a US immigration raid that Hyundai warned will delay completion of its battery factory.

South Korean workers accounted for most of the 475 people arrested last week at the Hyundai-LG battery plant under construction in Georgia, prompting tense negotiations between Seoul and Washington, staunch security allies.

A specially chartered Korean Air Boeing 747-8I carrying 316 South Koreans and 14 foreign employees departed Atlanta's Hartsfield-Jackson International Airport on Thursday, Seoul's foreign ministry said.

"Everything at Atlanta went smoothly," a foreign ministry official told AFP on Friday, ahead of the workers' expected arrival at 2:00 pm (0500 GMT).

"The plane departed as scheduled with

See Full Page