Abe told parliament: "We must hold the Olympics
as a testament to humanity's victory over the coronavirus.
If we're not in such situation, it's difficult (to hold) the Games," he said, insisting the importance of developing vaccines and drugs.”
“We've been saying we will hold the Olympics and Paralympics in which athletes and spectators can participate safely and in a complete form. I think (the Olympics) cannot be held in a complete form if the pandemic is not contained,” he added
The pandemic has already forced a year-long delay of the Games, which are now scheduled to open on July 23, 2021.
Mori was asked by the Nikkan Sports
daily whether the Games could be delayed until 2022 if the pandemic remains a threat next year, to which he said: "No."
When the delay was announced last month, IOC President Thomas Bach and Japanese Prime Minister Shinzo Abe decided the Tokyo Games would not be held beyond the summer of 2021.
"In that case, it's cancelled," he said in the interview published on Tuesday.
A Tokyo 2020 spokesman told reporters also on Tuesday that Mori's remarks were based on "the chairman's own thoughts".
Postponing the Games is an enormous logistical and financial challenge, with the final price tag for the delay still unclear.
IOC official disagrees COVID-19 vaccine needed for Olympics
However, in other development, the head of the International Olympic Committee’s (IOC) coordination commission for the Tokyo Olympics has said that he disagrees with suggestions by some scientists and doctors that a vaccine for Covid-19 is needed to hold the games.
John Coates, an International Olympic Committee member from Australia who is also a lawyer, said he had seen the opinion but didn't agree.
The advice we're getting from WHO (World Health Organization) says we should continue to plan for this date and that is what we're doing, and that's not contingent on a vaccine, Coates told the Australian Associated Press.
A vaccine would be nice. But we will just continue to be guided by WHO and the Japanese health authorities.
On Tuesday, Japan Medical Association president Yoshitake Yokokura said it would only be possible for the Olympics to go ahead in July 2021 if the infections were under control, not only in Japan, but globally.
In my view, it would be difficult to hold the Olympics unless effective vaccines are developed, Yokokura said.
Coates offered no details how 11,000 Olympians and 4,400 Paralympians from more than 200 nations and territories could safely enter and exit Japan without spreading the virus. They would be housed together in the Athletes Village.
They would also be accompanied by thousands of staff members and coaches, and thousands more technical officials who have to run the events. Add to this thousands of world broadcasters, who pay billions for the rights to the Olympics a critical element, particularly if the Olympics are held with limited numbers of spectators.
Coates said a lot of work had been done since the postponement and the target was still to have 43 venues for the Tokyo Olympics and Paralympics.
Coates was speaking in Australia a day after Yokokura told a video media conference of his concerns.
Earlier, Devi Sridhar, a professor of Global Health at the University of Edinburgh, also said holding the Olympics may depend on finding a vaccine. The same could apply to the 2022 Winter Olympics in Beijing.