Japan's most senior medical adviser says hosting the Olympics during the nation's current state of coronavirus infections was "not normal" in one of the strongest warnings yet about risks from holding the troubled Games.
Doctors have said the Olympics, due to start on July 23 after postponement from last year, would strain a healthcare system already seeing record numbers in critical condition.
Only 2.7 per cent of Japanese have completed inoculations, a Reuters tracker shows. The pace of new infections has, however, slowed.
Addressing a parliamentary committee, medical adviser Shigeru Omi said organisers should explain to the public why they are going ahead in the middle of a pandemic.
"It's not normal to hold the Olympic Games in a situation like this," said Omi.
Polls show most people in Japan are opposed to holding the Games, concerned about tens of thousands of athletes, officials and media descending on the country, where last week a state of emergency in Tokyo and other areas was extended to June 20.
"If we are going to hold the Games under these circumstances ... then I think it's the Olympic organisers' responsibility to downsize the scale of the event and strengthen coronavirus control measures as much as possible," Omi added.
The soft-spoken Omi's unusually stark comments contrasted with Japanese Prime Minister Yoshihide Suga and organisers who have reassured the world they can stage a "safe and secure" Games.
Meanwhile, around 10,000 of the 80,000 volunteers who signed up to help at the Tokyo 2020 Olympic and Paralympic Games have quit, broadcaster NHK reported, citing organisers.