Tokyo Olympics organisers say fans cannot sing or chant to support athletes, after they unveiled a 'playbook' detailing COVID-19 measures for this year's Summer Games.
The playbook states athletes and officials should not use public transport without permission, and asks them to wear face masks at "all times" during the event, except when eating or sleeping.
Officials say they must make a decision by April or May on the number of overall spectators allowed to attend.
Japan has been hit less severely by the pandemic than many other advanced economies, with fewer than 6000 deaths recorded so far, but a recent surge in cases forced it to close its borders to non-resident foreigners and declare a state of emergency in some parts of the country.
Public fears that an influx of athletes will spread the virus, with polls showing most Japanese residents oppose the Games taking place this year.
A Tokyo 2020 organising committee member says ensuring that the local medical system and the Olympics were both sustainable is important.
International Olympic Committee games operations director Pierre Ducrey says the Games will be a "different experience".
Delegations and staff will be required to appoint a COVID-19 liaison officer, who will be responsible for ensuring the participants follow the guidelines.
The playbook also advises against shopping at the airport upon arrival in Japan.