The International Olympic Committee and the Japanese government rescheduled the Games last month until July 2021 due to the COVID-19 pandemic. The head of Japan's medical association said it will be "difficult" to hold the Olympics without coronavirus vaccines, and he hopes effective vaccines or drugs to treat the disease will be developed quickly.

Mr.Mori said the Olympics and Paralympics might share opening and closing ceremonies instead of holding their usual separate events as a way to cut costs, though that idea is complicated by the fact that tickets have already been sold for all four ceremonies.

The Olympics planned for 1940 in Tokyo were canceled because of World War II.