SK Telecom and two smaller carriers had planned to initially launch 5G in South Korea on Friday with Samsung Electronics' new 5G-enabled smartphone Galaxy S10.

Verizon was due to roll out the technology in Chicago and Minneapolis on April 11, and said last month customers could use 5G on Motorola's Z3 and a "Moto Mod", a physical magnet-like attachment for the phone.

Countries including South Korea, United States, China and Japan are racing to market 5G, hoping the technology will spur breakthrough in fields such as smart cities and autonomous cars.

The technology can offer 20-times faster data speeds than 4G long-term evolution (LTE) networks and better support for artificial intelligence and virtual reality with low latency.

Sometimes it can offer 100-times faster speeds.

South Korea claimed to be the first country to launch 5G, but that was disputed by U.S. carriers who say they rolled out 5G in limited areas as early as last year.

U.S. telco AT&T Inc said it was the first to launch a "commercial and standards-based" 5G network in December 2018. The service, however, was made available to mobile hotspot devices but is not yet on phones.

SK Telecom spokeswoman Irene Kim told Reuters the company had internal discussions and decided to launch the 5G service early as the company had networks and customers ready.

South Korean carriers started offering 5G services at 11 p.m. local time (1400 GMT) on Wednesday.

FANFARE

In South Korea, telcos and smartphone makers are pulling out all stops to market 5G services and devices.

On Wednesday, SK Telecom showed off K-pop stars and an Olympic gold medallist as its first 5G customers.

The company said it was working with its memory-chip making affiliate SK Hynix to build a highly digitised and connected factory powered by 5G technology.

Smaller rival KT Corp said it will offer cheaper 5G plans than its LTE service, with unlimited data and four-year instalments to buy 5G devices.

Samsung was the first to unwrap a 5G phone in February when it unveiled the Galaxy S10 5G and a nearly $2,000 folding smartphone, putting the world's top smartphone maker by volume in pole position in the 5G race, some analysts say.

LG Electronics Inc plans to release its 5G smartphone in South Korea later this month.

SECURITY CONCERNS

While security concerns over 5G networks using telecom equipment made by China's Huawei Technologies Co Ltd have marred the buildup to the release of these services, South Korean telcos have tried to shrug them off.

"I don't think we have a security issue in South Korea," Park Jin-hyo, head of SK Telecom's information and communication tech research centre, told reporters.

He added the company uses advanced technology to block eavesdropping or hacking into 5G networks.

Among South Korea's three operators, SK Telecom and KT Corp do not use Huawei equipment for 5G. Smaller carrier LG Uplus Corp uses Huawei gear.

But SK Telecom officials said it was likely there will be an open auction for network equipment makers including Huawei if South Korea needs more base stations for higher frequencies. The country has one of the world's top smartphone penetration rates.

(Reporting by Ju-min Park in Seoul and Kenneth Li in New York; Editing by Diane Craft, Sayantani Ghosh and Himani Sarkar)

By Ju-min Park and Kenneth Li