Factbox: Coronavirus outbreaks at the Tokyo Olympics

Yet a number of cases have emerged involving athletes and other people involved with the Games. 

The following is a list to date, in chronological order. 

JUNE 20 - A coach with Uganda's squad tests positive on arrival at Narita airport and is quarantined at a government-designated facility. The rest of the team heads by bus for their host city, Izumisano near Osaka in western Japan. 

JUNE 23 - A Ugandan athlete tests positive, Izumisano officials said. 

JULY 4 - A member of Serbia's Olympic rowing team tests positive on arrival. The other four team members are isolated as close contacts. 

JULY 9 - One Lithuanian and one Israeli athlete test positive, according to reports. Later reports say the Lithuanian's results were unclear and subsequently tested negative. 

JULY 14 - A masseur for the Russian women's rugby sevens team tests positive, forcing the team into isolation for two days, the RIA news agency reports. Officials in Munakata, southwestern Japan, confirmed one staff member was hospitalised and said none of the team members could be considered close contacts. 

- The refugee Olympic team delayed its arrival in Japan following a positive case with a team official in Doha. The infected official is in quarantine without symptoms and 26 of the 29 refugees will remain in their Doha training camp. 

- Seven staff at a hotel in Hamamatsu, central Japan, where dozens of Brazilian athletes are staying, have tested positive, a city official said. 

- Twenty-one members of the South African rugby team are in isolation after they are believed to have been in close contact with a case on their flight. 

JULY 15 - Eight athletes from the Kenya women's rugby team were classified as close contacts after a positive coronavirus case was found on their flight to Tokyo, said an official with the southwestern city of Kurume, where they were set to hold a training camp. 

- U.S. basketball star Bradley Beal’s Olympic dream was cut short 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. 

- An Olympic athlete under a 14-day quarantine period tested positive for the virus, but had not yet moved to the Olympic Village, the organising committee's website reported, without giving further details. They said one member of the Games personnel and four Tokyo 2020 contractors had also tested positive. 

JULY 16 - Australian tennis player Alex de Minaur tested positive for COVID-19 prior to his departure for the Tokyo Olympics, the Australian Olympic Committee said. 

- A member of the Nigerian Olympics delegation who tested positive for the coronavirus at Narita airport on Thursday has been admitted to a hospital, media said. The person, in their 60s, had only light symptoms but was hospitalised because of their advanced age and pre-existing conditions, TV Asahi said, adding it was the first COVID-19 hospitalisation of an Olympics-related visitor. No further details were available. 

- An Olympic-related non-resident under a 14-day quarantine period tested positive for the virus, the organisers' website said, without giving further details. Three Tokyo 2020 contractors, all of whom are residents of Japan, also tested positive, organisers said. 

JULY 17 - 15 people tested positive for the virus, the organisers said, including the first case at the athletes' village, who is a visitor from abroad and is involved in organising the Games. The rest are two members of the media, seven contractors and five members of the Games personnel. 

JULY 18 - Ten people, including two athletes staying at the athletes' village, tested positive for the virus, the organisers said. This is the first time athletes have been found positive within the village, where most competitors will be staying. 

The others were one athlete under a 14-day quarantine period, one member of the media, one contractor and five Games personnel. All of the 10 are non-residents of Japan.