South Korea has claimed it beat the US by a matter of hours to become the first country to roll out a super-fast 5G mobile network, which allows users to download entire movies almost instantaneously.

Three South Korean carriers – SK Telecom, KT and LG Uplus – launched 5G services at 11pm local time on Wednesday, according to media reports, but only for a handful of celebrities in what their US rival dismissed as a publicity stunt.

“SK Telecom [has] announced that it has activated 5G services for six celebrities representing Korea as of 11pm 3 April 2019,” the country’s biggest mobile operator said in a news release on Thursday.

The launch was reportedly brought forward by two days, as speculation mounted that the US mobile carrier Verizon planned to launch its own service ahead of schedule and claim the title of the world’s first 5G provider.

A KT technician checks an antenna for the 5G mobile network service in Seoul. Photograph: Jung Yeon-Je/AFP/Getty Images

With national pride at stake, South Korean government regulators modified service terms so that the carriers could quickly sign up half a dozen celebrity customers, including two members of the K-pop band EXO and the former Olympic figure-skating gold medalist Kim Yuna.

Verizon’s 5G service also appeared on Wednesday in parts of Chicago and Minneapolis – a week ahead of its scheduled 11 April launch but a little later than the three South Korean carriers, according to Yonhap news agency.

The US firms said it planned to introduce the new service in more than 30 locations across the country by the end of the year.

Ordinary consumers in South Korea, which has one of the world’s highest smartphone penetration rates, will be able to connect to 5G services from Friday – the original launch day – when Samsung begins sales of the Galaxy S10 5G, the world’s first available smartphone with the technology built in. LG Electronics will release its 5G smartphone later this month.

South Korea’s three carriers plan to expand their combined coverage to 85 cities by the end of the year.

Verizon’s network will work with Lenovo’s Moto Z3 smartphone fitted with a special accessory, while rival US carrier AT&T launched a 5G-based system in parts of 12 cities in December, although it is only accessible to invited users through a free hotspot device, rather than paying customers with mobile phones.

Despite South Korea’s claim to have won the battle for 5G bragging rights, Japan’s Nikkei business paper said the race may still be too close to call, noting that Verizon’s announcement was made at 11am US eastern time, while South Korea’s SK said it had switched on its service an hour earlier.

Verizon, however, dismissed SK’s launch as a publicity stunt.

“They gave phones to six celebrities and they’re trying to say that constitutes a network launch? That’s a PR stunt,” Kevin King, director of corporate communications at Verizon, told the Nikkei.

“We launched a network and made 5G devices available for any customers that wanted them. We had devices in stores in Chicago and Minneapolis, and available for purchase online.”

Officials in South Korea, meanwhile, claimed the country’s reputation as a hyper-connected society had been enhanced – if only by a whisker.

“The government and private companies came together to achieve the world’s first commercialised 5G services and this proves once again our country is undoubtedly the top powerhouse in information and communications,” said You Young-min, South Korean minister for science and information technology.

The US and South Korea are among several countries hoping for a share of 5G-related economic benefits estimated to be worth US$565bn globally by 2034, according to the Global System for Mobile Communications in London.

Chinese firms have invested heavily in the technology, while Japan’s mobile carriers plan to have a full 5G service in place in time for the 2020 Tokyo Olympics.

Patents for 5G are dominated by Chinese companies, with 3,400 5G patents – including 1,529 registered by Huawei – followed by South Korea with 2,051 patents and the US with 1,368.

Officials in the US and Britain have warned that Huawei’s heavy involvement in 5G technology poses a security risk, as it could give Beijing access to connected utilities and other components.