Olympic rings are displayed at Japan Sport Olympic Square near national stadium in Tokyo, Japan on March 24. Photo: VCG

The postponed Tokyo 2020 Olympics will be canceled if the coronavirus pandemic isn't brought under control by next year, the organizing committee's president said.

The pandemic has already forced a year-long delay of the Games, which are  rescheduled to open on July 23, 2021, but Tokyo 2020 President Yoshiro Mori said no further postponement was ­possible.

In an interview with Japan's Nikkan Sports daily, Mori was categorical when asked if the Olympics could be delayed until 2022 if the pandemic remains a threat next year, replying "No."

"In that case, it's canceled," Mori said.

Mori said the Games had been canceled previously only during wartime and compared the battle against coronavirus to "fighting an invisible enemy".

If the virus is successfully contained, "we'll hold the Olympics in peace next summer," he added. 

Under heavy pressure from athletes and sports associations, Japanese organizers and the International Olympic Committee agreed in March to a year-long postponement of the Games.

Organizers and Japanese officials have said the delayed Olympics will be a chance to showcase the world's triumph over the coronavirus, but questions have arisen about whether even a year's postponement is sufficient.

On Tuesday, the head of Japan Medical Association warned it would be "exceedingly difficult" to hold the Games next year if a vaccine had not been found.

"I would not say that they should not be held, but it would be exceedingly difficult," Yoshitake Yokokura told reporters.

And last week a Japanese medical expert, who has criticized the country's response to the virus, warned that he was "very pessimistic" that the postponed Olympics can be held in 2021.