Japan is considering banning all spectators from the Olympics with authorities expected to declare a state of emergency for Tokyo to contain coronavirus infections 16 days before the Games begin.
Prime Minister Yoshihide Suga said his government would decide on new measures to stop the spread of the virus on Thursday. Those measures are expected to determine whether spectators can attend Olympic events.
Medical experts have said for weeks that having no spectators at the Olympics would be the least risky option amid widespread public concern that the Games will fuel new surges of coronavirus infections.
Organisers have already banned overseas spectators and set a cap on domestic spectators at 50 per cent of capacity, up to 10,000 people, to contain a lingering coronavirus outbreak.
Officials have been wrestling with the question for months but a ruling party setback in a Tokyo assembly election on Sunday, which some allies of Prime Minister Suga attributed to public anger over the Games, had forced their thinking, sources said.
"Politically speaking, having no spectators is now unavoidable," a ruling party source told Reuters.
Japan will hold a general election later this year and the government's insistence that the Games - postponed last year as the virus was spreading around the world - should go ahead this year could cost it at the ballot box.
The Tokyo 2020 organising committee said restrictions on spectators would be based on the content of Japan's coronavirus state of emergency or other relevant measures.
Japan has not experienced the kind of explosive COVID-19 outbreaks seen elsewhere but has had more than 800,000 cases and 14,800 deaths.
Authorities have struggled to stamp out persistent clusters of infections, particularly in and around the capital, Tokyo, which reported 920 new daily cases on Wednesday, the highest since May 13.
A slow rollout has meant only a quarter of its population has had at least one COVID-19 vaccination shot.
Suga told reporters a decision on virus restrictions would be made on Thursday after talks with health experts. He vowed to respond to Tokyo's rising cases.
The Sankei daily, citing government sources, said the government was preparing to declare a state of emergency for Tokyo to contain the virus. The Nikkei newspaper later said the new emergency would last until August 22.
That could mean a ban on spectators at Olympic events as restrictions already in place in the city would be strengthened beyond an original end-date of July 11. Sankei said a "quasi emergency" in place in three prefectures neighbouring Tokyo, which will host some Olympic events, would be extended.
The Games begin on July 23 and end on August 8.