In a question and answer-style statement on its website yesterday, the IOC said Abe had "agreed that Japan will continue to cover the costs it would have done under the terms of the existing agreement for 2020, and the IOC will continue to be responsible for its share of the costs".

"For the IOC, it is already clear that this amounts to several hundred millions of dollars of additional costs," the IOC added, repeating a comment made by President Thomas Bach in an interview with a German newspaper last weekend.

While Japan is obligated to cover added costs in the Host City Contract for the 2020 Olympics and Paralympics it signed with the IOC in 2013, the statement prompted chief cabinet secretary Yoshihide Suga to deny any agreement had been reached.

"It's not true there has been an agreement on an additional cost burden," he said.

The IOC has since deleted the statement, which has sparked an open conflict with organisers, referencing Abe and an agreement regarding the additional costs, reported by Kyodo News to be around $3 billion (£2.4 billion/€2.8 billion).

Tokyo 2020 spokesperson Masa Takaya said organisers had asked the IOC to remove the comment, telling a teleconference involving Japanese media that it was "not appropriate for the Prime Minister's name to be quoted in this manner".

In an update to the post today, the IOC said: "The IOC and the Japanese side, including the Tokyo 2020 Organising Committee, will continue to assess and discuss jointly the respective impacts caused by the postponement."

The u-turn from the IOC adds to already considerable uncertainty surrounding numerous areas of the organisation of the rescheduled Games and will be viewed by some as the IOC's latest communications error.

The IOC faced criticism from athletes and others for continuing to insist Tokyo 2020 would take place as planned this year, despite the rapid spread of the COVID-19 virus, which eventually led to the postponement of the Games until 2021.

Tokyo 2020 chief executive Toshirō Mutō had previously admitted the decision will result in "massive" extra costs.

The IOC has conceded adjustments will be required to reduce additional expenditure, while John Coates, chair of the IOC Coordination Commission for Tokyo 2020, said last week those involved in the organisation of the Games would assess "all opportunities to explore the scope and service levels" at the rearranged event to find savings.

Coates also suggested some of the "nice haves" at the event, such as live celebration sites across Japan, would have to be cut to save additional costs.