A senior Olympics official has warned that holding the postponed Tokyo Games next year faces "real problems", with even a vaccine unlikely to stave off the threat of the coronavirus.
John Coates, the International Olympic Committee's pointman for Tokyo 2020, indicated that officials would start deciding in October if and how the pandemic-hit Games could go ahead in July 2021.
He told a roundtable organised by Australian media giant News Corp that Japanese Prime Minister Shinzo Abe has been clear the Tokyo Olympics could not be delayed a second time.
"We can't postpone it again and we have to assume that there won't be a vaccine or, if there is a vaccine, it won't be sufficient to share around the world," he said.
Without the safety net of a widely available vaccine, there could be enormous challenges in screening tens of thousands of people from all corners of the world, he said.
"We've got real problems because we've got athletes having to come from 206 different nations," said Coates.
"We've got 11,000 athletes coming, 5,000 technical officials and coaches, 20,000 media, we've got 4,000 working on the organising committee there at the moment, there will be 60,000 volunteers coming. There's a lot of people."
Coates said if there are signs the pandemic is contained, even if not eradicated, by October, officials will start preparing "the different scenarios by which the sport could take place".
He said: "Do we quarantine the Olympic village? Do all athletes when they get there go into quarantine? Do we restrict having spectators at the venues? Do we separate the athletes from the mixed zone where the media are?"
On Thursday, IOC president Thomas Bach appeared to have accepted that the Games will have to be held next year – or not at all.
“Quite frankly, I have some understanding for this, because you can’t forever employ 3,000 or 5,000 people in an Organising Committee,” Bach told The BBC.
“You can’t every year change the entire sports schedule worldwide of all the major federations. You can’t have the athletes being in uncertainty.”
Asked whether the Olympics could be staged behind closed doors, Bach said: "This is not what we want. Because the Olympic spirit is about also uniting the fans and this is what makes the games so unique that they're in an Olympic stadium, all the fans from all over the world are together.
"But when it then would come to the decision … I would ask you to give me some more time for consultation with the athletes, with the World Health Organization, with the Japanese partners."