The head of a Japanese doctors union called Thursday for the cancellation of the Tokyo Olympics, set to begin in less than two months, saying staging the games would be "extremely dangerous" as Japan is already facing a fourth wave of coronavirus infections.

With an expected influx of nearly 100,000 athletes, staff and officials for the Olympics and Paralympics, Naoto Ueyama, head of the Japan Doctors Union, warned that "all different kinds of mutant strains of the virus that exist in various places will be concentrated and gathered here in Tokyo."

At a press conference in Tokyo, he said, "We cannot deny the possibility of even a completely new strain of the virus potentially emerging" and spreading around the world from the Japanese capital if the Olympics and Paralympics are held this summer.

The labor union Ueyama leads is one of many small groups representing physicians in Japan, but its staunch opposition reflects the overall view of the Japanese public regarding the Olympics.

The Tokyo Games organizers' insistence on pushing ahead despite the pandemic has fueled negative sentiment toward the games as Tokyo and some other areas of the country have been under a state of emergency since late April due to a spike in infections driven by the spread of variants of the virus.

A comment by International Olympic Committee Vice President John Coates during an online press conference last week saying the games will open July 23 even if Tokyo is under a COVID-19 state of emergency has caused a firestorm.

Describing the health care system in the western prefecture of Osaka as in "a state of collapse," Ueyama said at the Foreign Correspondents' Club of Japan that medical resources are strained across the country, leaving doctors and nurses exhausted.

Given that Japan is lagging far behind other developed countries in vaccination rates and polymerase chain reaction tests, he said hosting the Olympics would be "irresponsible with regard to the athletes."