FILE: Nigeria's flag bearer Sinivie Boltic holds the national flag during the opening ceremony of the London 2012 Olympic Games in England, July 27, 2012. Nigeria did not win a single medal at the London games, and the signs are not good for Rio. Reuters

A member of the Nigerian Tokyo Olympics delegation became the first Olympics visitor admitted to hospital with COVID-19, Japan's TV Asahi reported on Friday, as Japan battles to stem rising local infections with the Games a week away.

The person, a non-athlete in their 60s, tested positive on Thursday evening at the airport and had only mild symptoms but was hospitalised because of their age and pre-existing conditions, TV Asahi said, without giving further details.

Earlier in the day, the Australian Olympic Committee said that Australian tennis player Alex de Minaur, ranked 15th in the world, had tested positive for COVID-19 prior to his departure for the Tokyo Olympics, the latest athlete to see his Olympics dream shattered by the virus.

U.S. basketball star Bradley Beal’s Olympic dream was cut abruptly short on Thursday when USA Basketball announced the Washington Wizards star will miss the Tokyo Games after he entered coronavirus protocols at the training camp in Las Vegas.

Several COVID-19 cases have emerged involving athletes and others involved with the Games, which start July 23, even as infections spread in Tokyo and experts warn worse may lie ahead.

Tokyo is under a state of emergency for the pandemic, but most steps to curb its spread are voluntary and many people say they have grown weary of complying.

"We're very disappointed for Alex," Australia's Chef de Mission Ian Chesterman told reporters on Friday.

"He said that he's shattered, not being able to come ... but he has sent his very best wishes for the rest of the team."

De Minaur returned two positive tests in Spain before he was due to fly to Japan, David Hughes, the AOC's chief medical officer, told a news conference.

Organisers have promised that the Games, postponed last year because of the pandemic, will be "safe and secure" and imposed strict testing regimes and limits on delegates activities to try to soothe concerns amongst the general public, many of whom wanted the Games cancelled or postponed again.

FLEXIBILITY NEEDED

International Olympic Committee President Thomas Bach said on Thursday there was "zero" risk of Games participants infecting Japanese residents with COVID-19, as cases hit a six-month high in the host city.

However, Japanese Olympic gold medalist turned chief of the Japan Sports Agency, Koji Murofushi, told Reuters on Friday that Olympics organisers needed flexibility and swift decision-making in reacting to the spread in COVID-19 infections.

"It's possible that even after the Olympics start, there will be situations where we'll need to add measures to prevent the spread of infections - and if that's the case, we have to be flexible enough to act swiftly," said Murofushi, 46, a gold and bronze medalist in the hammer throw.

The Tokyo Games will be held without spectators at most venues, and officials are urging the public to stay home and watch on TV, depriving Japan of its hopes for a Games with pomp and public spectacle.

Bach had suggested to Prime Minister Yoshihide Suga that if the coronavirus situation improved then spectators should be allowed into stadiums to watch the Games, media reported.

Asked about the report, Tokyo Governor Yuriko Koike told reporters while many hoped children at least could see the Games in person, it would depend on the trend in infections.

BACH VISITS HIROSHIMA

Bach on Friday visited Hiroshima, the first city to suffer an atomic bombing, to deliver what organisers have called a message of peace on the first day of an "Olympic Truce", an ancient tradition to cease hostilities during the Games.

Bach laid a wreath at the Hiroshima Peace Memorial Park cenotaph and called the Games a "beacon of hope" for a peaceful future.

But the visit has proved controversial, with some critics charging the IOC of using it as a publicity stunt and others worried about contagion.

Japan has not suffered the explosive outbreak seen elsewhere, recording more than 820,000 cases and about 15,000 deaths. But host city Tokyo had 1,308 new cases on Thursday and another 1,271 on Friday.

The city's COVID-19 monitoring committee warned on Thursday that if the pace of contagion picked up as people move around and new, highly transmissible variants spread, the seven-day moving average could nearly double to 2,406 in four weeks.

That would approach the highest levels seen yet in the course of the pandemic.

Japan's rocky vaccination rollout has also sparked frustration among the public and the municipal authorities that handle much of the programme. An initially slow start gained momentum, only to hit roadblocks due to supply bottlenecks and only 31% of people have had at least one shot.