The IOC's announcement has disappointed and frustrated officials in Tokyo who have been making arrangements for the events.
A senior official of the Tokyo metropolitan government said the marathon and race walking events can entertain thousands of people without tickets as they can line the streets to cheer on the athletes.
The official said it seems the efforts and preparation by volunteers and city workers will have been in vain.
Tokyo Governor Yuriko Koike said the abrupt announcement raises many issues.
She said the city has taken a range of measures to address the summer heat, and that she was taken by surprise by the sudden announcement.
Koike added she will ask the IOC to give a full explanation to all people concerned.