Tokyo 2020 organisers have announced spectators will not be allowed to travel from overseas to watch the Olympic Games this year.
The measure has been taken as part of an effort to reduce the risks of COVID-19 spreading at the delayed Games.
The Games will run from July 23 to August 8, having been set back by a year due to the global health crisis.
Also affected will be the Paralympics, which runs from August 24 to September 5, with travelling spectators also barred from attending.
The International Olympic Committee (IOC) and International Paralympic Committee (IPC) have been advised of Tokyo's decision and are said by Games chiefs to "respect and accept this conclusion".
In a statement issued on Twitter, Tokyo 2020 said: "Today, on March 20, we reported to the IOC and IPC that we would not accept overseas spectators to Japan in order to realise a safe and secure event.
"We will continue to do our utmost to make this summer's event a safe and secure event so that it will be a light of hope for people all over the world."
In a further statement, Tokyo 2020 organisers said tickets purchased by those planning to travel from abroad would be refunded.
They said the coronavirus situation within and beyond Japan "remains very challenging" and pointed to travel across borders being "severely restricted", meaning entry to Japan could not be guaranteed.
"In order to give clarity to ticket holders living overseas and to enable them to adjust their travel plans at this stage, the parties on the Japanese side have come to the conclusion that they will not be able to enter into Japan at the time of the Olympic and Paralympic Games," said the Tokyo 2020 statement.
"This conclusion will further contribute to ensure safe and secure Games for all participants and the Japanese public."