Organisers claimed that the move was necessary in order to reduce the risk of COVID-19 infections.

However, World Athletics has told insidethegames it is "surprised" by the decision which it describes as "seemingly inconsistent" with plans to allow up to 10,000 spectators to attend events at indoor venues.

Sapporo is the capital of Japan's northernmost island Hokkaido, which remains under state of emergency measures because of coronavirus.

Games officials today met with both Hokkaido prefecture and Sapporo city authorities, as well as the police, to go through the arrangements for the marathons and race walking.

"At the meeting, it was agreed that in view of the current COVID-19 situation, it will be necessary to reduce the risk of infection by restricting the movement of members of the public," a statement said.

"It has therefore been decided to ask the public to refrain from spectating along the course.

"We will continue to work closely with the Hokkaido prefectural authorities, the Sapporo City Government and all other relevant organisations to ensure a safe and secure Tokyo 2020 Games for all participants and for the citizens of Sapporo and Hokkaido."

In its statement World Athletics said: "We are surprised by this new decision about our events in Sapporo, which is seemingly inconsistent with the decision to allow up to 10,000 spectators in venues in Tokyo, many of which are indoor venues. 

"We will discuss this decision as soon as possible as it would be a great shame not to have spectators for the race walk and marathon events in Sapporo given the popularity of both disciplines in Japan and the fact they are being held outdoors."

Kyodo News had previously reported that Hokkaido Governor Naomichi Suzuki had asked for restrictions on fans at the events.

It is hoped that the prefecture's state of emergency measures will be lifted on July 11.

Sapporo, which hosted the Winter Olympics in 1972, lies 800 kilometres north of Tokyo but was named as the venue for the Olympic marathons and race walking in October 2019.

The decision, taken before COVID-19 caused the delay of Tokyo 2020 by a year, was made due to fears about high temperatures in the capital.

It was a move which resulted in the International Olympic Committee clashing with Tokyo Governor Yuriko Koike, who opposed the decision, and some athletes. 

Odori Park will be the start and end point for both marathons.

The route features a large loop which is about the length of a half-marathon, followed by a second smaller loop which will be completed twice.

The fact that fans have been asked not to attend the marathons, which take place in the open air and are traditionally free for the public, is another blow for spectators as the Olympic Opening Ceremony approaches on July 23.

Tokyo 2020 yesterday delayed the results of a ticket lottery until Saturday (July 10) as organisers continue to assess the number of spectators that will be permitted in each venue.

International fans have already been banned.