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With the opening ceremony only three days away, an Olympics chief has not ruled out a last-minute cancellation of the Tokyo Games.
It comes amid rising coronavirus cases which are presenting organisers with mounting challenges.
Asked at a press conference conference if the Games, which are due to open on Friday, might still be cancelled, Toshiro Muto said he would watch infection numbers and hold discussions with organisers if necessary.
The CEO of the Tokyo Organising Committee said on Tuesday: "We can't predict what will happen with the number of coronavirus cases. So we will continue discussions if there is a spike in cases.
"We have agreed that based on the coronavirus situation, we will convene five-party talks again. At this point, the coronavirus cases may rise or fall, so we will think about what we should do when the situation arises."
There are fears the Games' COVID-19 isolation "bubble" system has already burst after a number of cases emerged among athletes and other people involved.
The first cases among competitors were reported on Sunday in the Tokyo village were 11,000 athletes are set to stay. Overall, there have been 67 infections detected among those accredited for the Games since 1 July.
Kenji Shibuya, the former director of the Institute for Population Health at King's College London, said: "It's obvious that the bubble system is kind of broken.
"My biggest concern is, of course, there will be a cluster of infections in the village or some of the accommodation and interaction with local people."
COVID cases are also rising in Tokyo and the Games, postponed last year because of the pandemic, is set to be held without spectators.
Earlier this month, Japan decided participants would compete in empty venues to minimise the risk of further infections.
There has been growing domestic anger about coronavirus restrictions and a possible spike in cases triggered by Games attendees arriving from abroad.
Public health experts have warned seasonal factors, increased mobility and the spread of the Delta variant could lead to a surge past 2,000 cases a day in Tokyo by next month – levels that could drive the city's medical system to breaking point.
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