SEOUL/SAN FRANCISCO, Jan 12 (Reuters) - More than 30 officials from major South Korean companies who attended the giant CES tech trade show in Las Vegas last week tested positive for COVID-19 while in the United States, industry sources said on Wednesday. About 20 officials from Samsung Electronics (005930.KS) and about six at SK Group, parent of energy firm SK Innovation (096770.KS) and chipmaker SK Hynix (000660.KS), were among those who tested positive for the virus after attending CES, the sources said. They declined to be identified as they were not authorised to speak to media. Hyundai Heavy Industries (329180.KS) said six of its employees who attended CES tested positive while in the United States and were quarantined, and some have been released since. Meanwhile "multiple" Hyundai Motor (005380.KS) and Hyundai Mobis officials who attended CES also tested positive after arriving back in South Korea, South Korean newspaper JoongAng Ilbo reported, citing an unidentified industry source without specifying the exact number of cases. Most of the Samsung officials who tested positive have were flown back to Korea from Nevada in two chartered flights, arriving late on Tuesday Seoul time, and the remaining Samsung officials are expected to be flown back on Wednesday, South Korean newspaper Chosun Ilbo reported, citing unidentified industry sources. The Samsung officials are being moved to quarantine facilities in South Korea and most were asymptomatic or have light symptoms, the paper said. A spokesperson for Consumer Technology Association (CTA), CES" operator, did not have an immediate response. Nevada state health authorities said, "Many new cases have had recent travel history, attended events, and have visited multiple locations where they could potentially have acquired their infection." They said they do "not have evidence linking the recent surge in COVID-19 cases with CES." Samsung Electronics declined to confirm details of the cases. It said it "took a number of steps to protect the health and well-being of (CES) attendees", including requiring vaccines, mask mandates, social distancing protocols and providing testing for all employees throughout the week. SK Group declined to confirm, citing its policy of not disclosing personal information. Hyundai Motor Group did not respond to multiple requests for comment. South Korea reported 381 cases of infections contracted overseas for Tuesday, a record, according to the Korea Disease Control and Prevention Agency, bringing the daily number of infections across the country to 4,388.